GF Income Tax

General reference only. This Guide is general tax/accounting reference material for AI-assisted workflows. It has not been reviewed for any specific person's facts, documents, elections, deadlines, residency, filing status, or local procedures. Do not rely on it to file, pay, amend, or take a tax position without review by a qualified professional in the relevant jurisdiction.

Who this applies to

This is the ordinary individual income-tax Guide for Guyane (French Guiana), part of France, not Guyana. A person fiscally domiciled there is within French resident taxation on worldwide income. CGI article 4 B tests the home/principal abode, a non-accessory professional activity, or the centre of economic interests; meeting a domestic test remains subject to treaty residence. Do not substitute a universal days-only test. CGI art.4 B; DGFiP DOM guidance.

Start with the income year, household members, residence and move dates, income categories, documented expenses, previous losses, relief elections and tax already withheld. Married/PACS couples generally file jointly; single individuals normally have one part and jointly assessed couples two, with child/dependant and shared-custody adjustments. Ordinary dependent children add half a part for each of the first two and one part from the third; shared-custody increments are halved and children with exclusive charge are counted first. A single parent living alone has separate first-child rules; disability, widowhood, adult attachment and changing family status require the special table. Compute the actual household's parts and family-quotient cap from its status, not from the salary of one spouse. DGFiP brochure, household pp.75-84 and calculation pp.369-372.

Year boundary: the 2026 filing campaign assesses 2025 income. The article 197 bands below are enacted for 2025 and following years as the law stands on the read date. They are a current-law planning basis for 2026 income, not an assertion that Parliament has fixed the 2027 assessment's future indexed figures or filing calendar. Every example explicitly uses 2025 income assessed in 2026. CGI art.197, commencement note.

The personal progressive-tax reduction belongs here. ZFANG business-profit relief belongs in gf-corporate-income-tax, including its application to eligible individual businesses; social contributions and payroll calculations belong in gf-social-contributions and gf-payroll. Non-resident computation, foreign withholding and treaties belong in gf-cross-border-tax. Specialist investment incentives, stock awards, life-insurance withdrawals, exceptional/high-income contributions and business or property disposal reliefs need their own current-law computation.

Rates, bands and thresholds

Amounts are EUR. The first eleven rows are 2025 income assessed in 2026 / current article 197, not an invented final 2027 rate card.

Item and conditions	Amount or rule	Official source
Per-part taxable income up to 11,600	0%	CGI art.197 I-1
Per-part income above 11,600 up to 29,579	11% on that slice	CGI art.197 I-1
Per-part income above 29,579 up to 84,577	30% on that slice	CGI art.197 I-1
Per-part income above 84,577 up to 181,917	41% on that slice	CGI art.197 I-1
Per-part income above 181,917	45% on that slice	CGI art.197 I-1
Ordinary family-quotient advantage cap	1,807 per extra half-part; half that per quarter-part, with statutory special-status exceptions	CGI art.197 I-2
Guyane domicile reduction	40% of progressive tax after family-quotient capping, maximum 4,050; before décote and other reductions	CGI art.197 I-3
Décote, single/divorced/widowed taxpayer	Positive 897 minus 45.25% of tax after preceding steps, limited to that tax	CGI art.197 I-4
Décote, jointly assessed couple	Positive 1,483 minus 45.25% of tax after preceding steps, limited to that tax	CGI art.197 I-4
Employee standard professional-expense deduction	10%; minimum 509 per person limited to salary, maximum 14,555 per person; actual-expense election replaces it	DGFiP 2026 brochure p.107, 2025 salary
Pension deduction, 2025 pensions	10%; minimum 454 per pensioner limited to pension, maximum 4,439 for the household; no employee actual-expense option	DGFiP 2026 brochure pension chapter p.117
Ordinary micro-BIC sales, 2026 regime	203,100 annual turnover excluding tax; prior-year/two-year regime test and start-year adjustment apply; excludes furnished residential letting	BOI-BAREME-000044 I-A
Ordinary micro-BIC services / micro-BNC, 2026 regime	83,600 turnover/receipts excluding tax; do not apply to unclassified tourist rentals	BOI-BAREME-000044 I-C and III
Ordinary micro-BIC expenses	71% of sales / 50% of service receipts; minimum 305, bounded by receipts; no extra actual-cost deduction	DGFiP independent professionals; CGI arts.50-0, 102 ter
Micro-BNC expenses	34% of receipts; minimum 305, bounded by receipts; no extra actual-cost deduction	DGFiP independent professionals
Micro-BA, 2026 regime	Prior three-year average receipts no more than 129,200; taxable base uses the prescribed average of the current and two previous years and 87% allowance, minimum 305	BOI-BAREME-000044 II; CGI art.64 bis; DGFiP allowance
Unfurnished ordinary rental micro-foncier	Household gross rent no more than 15,000, subject to property/regime exclusions; 30% allowance; real-regime election binds for three years	DGFiP rental guidance; CGI art.32
Ordinary rental deficit against global income	Non-interest deficit up to 10,700; excess and interest deficit against property income for ten following years; continued letting conditions apply	DGFiP rental guidance; CGI art.156 I-3
Ordinary investment income / securities gains income-tax component	Generally 12.8% flat income tax or global progressive-scale election; social levies separate and category/date dependent	DGFiP 2026 brochure, investment chapters
Capital-income social levies, general 2026 investment receipts	18.6%: CSG 10.6% + CRDS 0.5% + solidarity 7.5%; statutory exceptions and historical slices apply	CSS art.L136-8 I/IV; DGFiP
Unfurnished property-income social levies	17.2%: CSG 9.2% + CRDS 0.5% + solidarity 7.5%; net property-income base	DGFiP rental levies
Furnished letting not already charged as activity income by social authority	18.6% on relevant net taxable income, including non-professional letting; no double activity/patrimony charge	DGFiP rental levies
Qualifying EEA/UK/Swiss health-system affiliation, not borne by French compulsory system	CSG/CRDS exemption on qualifying property income; solidarity 7.5% remains; establish social affiliation and claim, not nationality alone	DGFiP rental levies
Valid micro versement libératoire election	1% ordinary sales, 1.7% BIC services, 2.2% BNC receipts, collected with micro-social payments; social contributions additional	DGFiP micro tax
2026 versement libératoire income condition	Household 2024 RFR no more than29,315 per part, adjusted for actualN-2 household parts; micro-BIC/BNC and micro-social membership also required	DGFiP current option conditions
Ordinary global deficit carry-forward	Six following years, only for losses legally deductible globally; category-ringfenced losses differ	BOI-IR-BASE-10-20 §1; CGI art.156

Social levy dates follow two different collection categories: LFSS 2026 article 12 (law 2025-1403 of 30 December 2025) applies the increased general CSG to 2025 income assessed under CSS L136-6, but to investment products under CSS L136-7 from 1January 2026, with historical/accrued-product exceptions. Ordinary 2025 interest/dividends already socially withheld in 2025 therefore cannot simply be reassessed using the 2026 receipt rate. Unfurnished property income and statutory excluded products retain the lower CSG rate. LFSS 2026 art.12II; CSS L136-8IV; Service Public resident tables.

Investment social levies are additional to income tax. The ordinary 2026 flat package on covered interest/dividends is 12.8% income tax plus18.6% social levies, total 31.4%, without extending it to every life-insurance/historical product. LivretA, LEP, LDDS and qualifying other statutory savings exemptions are tested separately. Under progressive assessment, qualifying CSG is deductible at 6.8% in the payment year, normally prefilled6DE; no such deduction for PFU income. Patrimony levies are assessed on the annual notice; domestic financial payers generally precollect investment levies. Verify a foreign payer's reporting/payment obligations separately. DGFiP securities; DGFiP rental levies; Service Public payment/exemption/deduction sections.

Furnished tourist accommodation has its own thresholds and allowances. Do not apply the ordinary sales allowance merely because rent is business income. The 2026 annual regime thresholds differ from the 2025 amounts shown in the 2026 return brochure. Current BOI-BAREME-000044.

The base

1. Classify receipts before combining them. Salaries and benefits use net taxable pay, pensions their own deduction, BIC commercial/accrual profits, BNC professional receipts less expenses in the default receipts/payment system (or a valid accrual election), BA agricultural rules, unfurnished rentals property rules and investment income its relevant flat/scale treatment. Partnership income may be taxed to partners even when cash is retained. DGFiP brochure, income chapters; independent professionals.
2. Salary expenses: report salary before the automatic expense deduction. For each employee compare the standard deduction with necessary, documented actual employment costs. An actual-expense election requires the relevant employer expense allowances/reimbursements to be included in taxable pay under the brochure's reimbursement rules; do not deduct the same cost twice. Private expenditure is excluded. Salary boxes 1AJ/1BJ and actual-expense boxes 1AK/1BK distinguish the choices. Brochure pp.107-111.
3. Business: micro means gross receipts on 2042-C-PRO and the statutory allowance, not profit after expenses. Under actual BIC/BA compute allowable business costs, stock/cut-off, depreciation and justified provisions; personal expenses, drawings, capital purchases deducted as current expenses and disallowed fines need adjustment. BNC normally deducts expenses necessarily incurred for the profession when paid, with capital assets handled through depreciation. Retain invoices and reconcile the results return to 2042-C-PRO. DGFiP independent professionals; CGI art.39 ordinary expense restrictions. A valid versement libératoire option changes income-tax collection for qualifying micro income; do not apply the progressive calculation to it as though no election existed. Its income still enters annual reporting and the effective-rate calculation for other income. For an existing business elect through Urssaf by30September of the preceding year; new businesses may elect by the last day of the third month following creation. Report the receipts in 2042-C-PRO5TA/5TB/5TE as appropriate, even after periodic tax was paid. If eligibility has ceased, the special credit/reclassification rules apply instead of pretending the payment remains final. The relevant current option conditions are DGFiP; also see brochure micro chapter.
4. Property: micro-foncier uses gross rent and no additional actual expenses. Under the real regime use 2044: deductible management, qualifying repairs/maintenance/improvement, insurance, property taxes and loan interest subject to each rule. Construction, reconstruction or enlargement is not an ordinary repair deduction. For a deficit isolate interest first; interest cannot create a global-income deduction. A global deduction normally requires letting through 31 December of the third year after the deduction year. Special energy-renovation and statutory rental incentives have separate conditions. DGFiP rental guidance; 2044 instructions.
5. Losses: genuine professional BIC/BNC deficits generally offset other household income and unabsorbed global losses carry forward as above. Non-professional BIC and non-professional BNC losses are ringfenced to qualifying same-category income, normally for six following years; furnished non-professional rental losses use their separate ten-year ringfence and cannot offset salary. Capital/securities losses do not become general salary deductions. Keep schedules by origin, category and expiry year, use oldest available loss first and never reuse it. CGI art.156; BOI-IR-BASE-10-20; BNC loss guidance; brochure business-loss chapters.
6. Household taxable net income: combine only progressive-tax categories after their lawful allowances/losses, then deduct eligible global charges once. Maintenance payments require a legal/support obligation and need/evidence; the same child cannot generate both attachment and a maintenance deduction. For 2025 income, ordinary maintenance to an adult child is capped at EUR 6,855, with special doubled limits only where the statutory household/dependency conditions apply. Retirement-saving deductions depend on the individual's available pension ceiling and previous carry-forwards, shown on the tax notice; do not deduct employer-relieved contributions twice. For 2025 voluntary contributions deductible globally, the ordinary current ceiling starts at 10% of 2024 net professional income capped at 8 times the relevant social ceiling, a maximum EUR 37,094, or the floor EUR 4,637 if higher, then prescribed previous-year pension adjustments and unused ceilings. The brochure separately confirms 2026 contribution ceiling maximum EUR 37,680/floor EUR 4,710 based on 2025 net professional income, before required adjustments. The 2026 law extends new unused ceiling to the next five years; the transition preserves only unused 2023-25 ceilings for deductions in 2026, and later years phase in the extension. Use the current-year ceiling first, then valid older amounts oldest first; do not resurrect expired pre 2023 amounts. From 1January 2026 voluntary PER payments from the seventieth birthday cease to qualify for the relevant deduction. CGI art.163 quatervicies; BOI-IR-BASE-20-50-30 §§30-80. Contributions beyond available ceiling are not themselves carry-forward deductions. Jointly assessed spouses can elect ceiling pooling via 6QR. New French residents and occupational/self-employed plans have specific rules. Use the dedicated maintenance and retirement fields, not salary-expense boxes. Brochure pp.227-236.
7. Compute in order: divide net progressive income by actual parts; apply bands; multiply by parts. Apply the family-quotient advantage limit by comparison with the base-parts computation, including special-status relief where relevant. Apply Guyane reduction, then décote, then non-refundable reductions, then refundable credits and creditable withholding/advances. A non-refundable reduction cannot by itself create a refund. Separately compute flat-tax income and any special contribution. CGI art.197.

Common household reductions and refundable credits

These reliefs are claimed after computing tax; they do not reduce salary or business income. Apply them only to eligible expenditure actually borne by the household, with receipts and subsidies reconciled. The following statutory rates and ceilings also govern 2026 expenditure under the law read on 11 November 2026; the return boxes below are the issued 2026 return for 2025 expenditure, not unissued 2027 fields.

Ordinary relief	Rate, expenditure limit and conditions	Official source
Donations to qualifying general-interest bodies	Non-refundable reduction of 66% of qualifying gifts, within 20% of taxable household income; excess gifts above that income limit carry forward five years, oldest first	CGI art.200(1)/(1 bis); BOI-IR-RICI-250-30 §§1-35/90-150
Qualifying gifts for persons in difficulty or domestic-violence victims	75% on a common EUR2,000 annual gift limit for gifts from 14 October 2025; 2025 gifts through 13 October have a EUR1,000 sublimit within that annual EUR2,000 ceiling. Excess qualifying gifts join the 66%/20%-of-income calculation; the 75% slice is outside that 20% limit	CGI art.200(1 ter); BOI-IR-RICI-250-30 §§30-35
Eligible home services	Refundable credit of 50% of net eligible costs; ordinary expense ceiling EUR12,000, plus EUR1,500 per dependent child, household member over 65 or qualifying over-65 ascendant, with the child increment halved for shared custody; ceiling after increments EUR15,000	CGI art.199 sexdecies(1)-(4); BOI-IR-RICI-150-20 §§120-145
Home-service special ceilings	First year claiming for direct employment: EUR15,000 before increments, maximum EUR18,000. Qualifying severe disability: EUR20,000 with no further increment. Within the applicable household ceiling, minor DIY EUR500 yearly and two hours maximum per intervention; home IT/internet EUR3,000; gardening EUR5,000	CGI art.199 sexdecies(3); BOI-IR-RICI-150-20 §§120-170; DGFiP home services
Childcare outside the home	Refundable 50% credit for a dependent child under six at 1 January of the expense year; expense cap EUR3,500 per child, hence credit maximum EUR1,750. Shared custody: each parent's expense cap EUR1,750 and credit maximum EUR875. Parents need not be working	CGI art.200 quater B; DGFiP childcare
Global tax-benefit cap	Home-service and childcare credits count toward the ordinary EUR10,000 annual cap shared with other covered incentives. Donations and the Guyane tax reduction are excluded. The EUR18,000 combined ceiling for specified overseas/SOFICA incentives does not increase the ordinary EUR10,000 allowance merely because the household lives in Guyane	CGI art.200-0 A(1)-(2)

Donations: check the recipient's legal eligibility and retain its tax receipt; a payment with a material personal benefit is not automatically a qualifying gift. The enhanced rate covers the statutory free meals, accommodation or principal medical-care activities and qualifying free support/rehousing of domestic-violence victims. For the 2026 return, ordinary French-body gifts use 7UF; enhanced gifts through 13 October 2025 use 7UD and later 2025 gifts 7UQ, with the aggregate ceilings applied once. EU/qualifying EEA recipients have separate eligibility/evidence and 2042-RICI fields. The carried amount is the unused gift above the income ceiling; an otherwise allowable reduction lost because tax is insufficient is not a refundable credit or a general carry-forward. DGFiP donation reporting; BOI §§90-150.

Home services: a French-tax-resident household may claim eligible domestic/family services at its French main or second home, through direct employment or a qualifying declared/authorised provider. Costs at a qualifying ascendant's home require the statutory APA conditions; the same ascendant cannot also generate a maintenance deduction for the claimant. Work-related or rental costs already deducted in an income category cannot be claimed again. Deduct APA/PCH, employer-funded CESU and other assistance. Off-premises services need the statutory bundled-service conditions and relevant spending limit; do not treat any delivery as eligible domestic work. For the 2026 return, report gross qualifying expenses in 2042 7DB and assistance in 7DR; complete 2042-RICI service-type details BDA-BEA, provider identity/nature and intervention method. Claim first-direct-employment status in 7DQ or qualifying disability in 7DG where applicable. Reconcile prefilled immediate credit advance 7HB and annual advance 8EA to avoid receiving the credit twice. CGI art.199 sexdecies; DGFiP home-service workflow; brochure pp.237-240.

Childcare: use an approved childminder or qualifying nursery/daycare, including eligible supervised time outside school lessons; the cost is for care outside the claimant's home. Exclude food and exceptional non-care extras, deduct CMG and employer/other childcare aid, and retain the provider's itemised statement. For 2025 care, the authority allows the specified childminder maintenance-cost element at EUR2.65 per care day; do not project that administrative daily amount to unissued 2027 instructions. Use 2042-RICI 7GA/7GB/7GC for exclusive/principal charge or 7GE/7GF/7GG for shared custody, one child per field. In-home childcare instead follows the home-service rules, with no double claim for the same expense. DGFiP childcare conditions and fields; brochure p.247.

Boundary	Treatment
Domiciled in Guyane at 31 December of the income year	Guyane reduction applies to the year's qualifying progressive tax, including earlier mainland income; address must reflect actual domicile
Guyane domicile on 1 January, then move to mainland during the year	Reduction only on the tax attributable to income received while domiciled in Guyane; retain dated income and move evidence
Micro business also eligible for ZFANG	Test the business relief separately using the corporate Guide; no assumption that all Guyane activities qualify
Flat-rate investment income	The Guyane reduction is a reduction of progressive tax; do not automatically reduce every flat withholding or capital levy
Treaty non-resident	Do not grant resident progressive/Guyane relief automatically; route to the cross-border Guide

Sources: DGFiP DOM address and move rules; CGI art.197; ZFANG §100.

Deadlines and filing

Registration and access: business commencement is declared through the INPI guichet unique; a micro-business social account does not replace the annual tax return. Obtain a numéro fiscal and personal Finances publiques access. A new filer without access uses the DGFiP registration/first-return procedure, rather than submitting an unprocessable scan through messaging. DGFiP micro guidance; 2026 campaign.

Annual workflow: log in at impots.gouv.fr → espace Finances publiques → declare income. Confirm civil status, household, dependant/shared custody and addresses/move dates. Review every prefilled taxable-income and withholding line against annual statements. Select annexes before entering additional categories. The 2026 forms for 2025 income use 2042 salary 1AJ/1BJ (actual expenses 1AK/1BK), pensions 1AS/1BS, micro-foncier 4BE or real property result 4BA from 2044; capital income is in section 2, with 2OP for the global progressive-scale election. Micro BIC ordinary sales use 2042-C-PRO 5KO/5LO, services 5KP/5LP, and professional micro-BNC 5HQ/5IQ; use the correct taxpayer and professional-status column. Foreign income needs 2047 and then the appropriate 2042 income and credit/exemption fields, not only an amount on the annex. Review 3916/3916-bis foreign-account reporting where applicable. 2026 brochure, reproduced forms and category instructions.

Actual business returns first: BIC uses 2031 and 2033-A to G or 2050 to 2059-G; BNC uses 2035 and its annexes; BA uses 2139 simplified or 2143 normal with its annexes. Submit electronically in the professional space/EDI as available. The normal results deadline is the second working day after 1 May following the relevant income/closing year, with the electronic extension where applicable. Reconcile any prefilled 2042-C-PRO result to the signed results return. A micro taxpayer normally reports receipts directly on 2042-C-PRO. DGFiP independent professionals; results filing.

For the 2026 return of 2025 income, the Guyane online deadline was 4 June 2026 at 23:59, paper when legally needed 19 May 2026 at midnight. Non-residents used the separate earlier deadline in the cross-border Guide. These dates are not the 2027 deadlines. 2026 calendar.

Sign and submit, save the acknowledgement and ASDIR where issued, then check the final assessment. The annual liability reconciles source deductions and self-employed/rental advances already paid; it is not cancelled by prélèvement à la source. Use “Gérer mon prélèvement à la source” to update circumstances and check bank details. On the 2026 campaign DGFiP schedules balances below EUR 300 in September and above EUR 300 across September-December; use the actual notice for the debit schedule and exact boundary. Refunds go to the recorded bank account or the administration's alternate method. The 2027 assessment's forms, indexed limits and administrative dates must be checked when issued. 2026 campaign.

Penalties and interest

Late annual IR filing generally brings 10% of tax; filing within 30 days after formal notice raises it to 20%; failing to file within those 30 days brings 40%; a discovered hidden activity can bring 80% without prior notice. The filing penalty base is the total tax before crediting advances/source deductions, whereas interest takes relevant payments into account. Interest is generally 0.20% per month, with statutory start/stop rules. CGI arts.1727, 1728, 1758 A; official sanctions guidance.

An ordinary inaccurate/omitted IR declaration can attract the article 1758 A 10% surcharge subject to spontaneous/notice-correction exceptions; deliberate understatement attracts article 1729 40%, fraudulent manoeuvres 80%, subject to the distinct abuse rules. Do not stack incompatible penalties for the same rights. Personal tax paid late is normally subject to 10% under article 1730, rather than importing the company-payment surcharge. Statutory correction and collection exceptions may remove or reduce a penalty. CGI art.1758A; CGI art.1729; CGI art.1730; BOI-CF-INF-10-30 II.

Cross-border points

Residence generally exposes worldwide income, but treaty allocation and credit/exemption methods must be applied income by income. A Brazilian or Surinamese payer does not establish an exemption by itself. Foreign tax may require gross income reporting, evidence and an explicit credit claim; overseas accounts can trigger a separate reporting duty even with no taxable receipt. See gf-cross-border-tax. CGI art.4 B; 2026 brochure, 2047 and foreign-account instructions.

Mainland France and Guyane are part of the same income-tax system. The distinct VAT/octroi border does not make a mainland salary foreign-source treaty income. Moves into/out of France require a residence-period split and possibly 2042-NR; a move between Guyane and mainland instead triggers the DOM-reduction rules above. DGFiP DOM guidance; brochure moves chapter.

Two worked examples that recompute

Example 1: one employee, Guyane reduction before décote

For 2025 income assessed in 2026, a single person with one part is domiciled in Guyane all year, has taxable salary EUR 50,000 before the standard expense deduction, and has no other income, special status, credits or reductions. Deduction = EUR 5,000; net income = EUR 45,000. Tax = (29,579 − 11,600) × 11% + (45,000 − 29,579) × 30% = EUR 6,603.99. Guyane reduction = EUR 2,641.596, below its cap. Remaining tax = EUR 3,962.394; décote is nil because its formula is negative. The illustration rounds final liability to EUR 3,962 before source-payment credits. CGI art.197; salary deduction.

name: Guyane single salary, 2025 income assessed in 2026
inputs:
  salary: 50000
steps:
  - expense_deduction: min(salary, max(509, min(salary * 0.10, 14555)))
  - net_income: salary - expense_deduction
  - band11: (min(net_income, 29579) - 11600) * 0.11
  - band30: (net_income - 29579) * 0.30
  - gross_tax: band11 + band30
  - guyane_reduction: min(gross_tax * 0.40, 4050)
  - after_guyane: gross_tax - guyane_reduction
  - decote: min(after_guyane, max(0, 897 - after_guyane * 0.4525))
  - final_tax: round(after_guyane - decote, 0)
expected:
  net_income: 45000
  gross_tax: 6603.99
  guyane_reduction: 2641.596
  final_tax: 3962

Example 2: choose actual employee expenses only after checking reimbursements

Same year and household, salary EUR 50,000, with EUR 8,000 qualifying actual costs and no employer expense reimbursements requiring add-back. Standard deduction yields the preceding EUR 3,962 rounded tax. Actual expenses instead give EUR 42,000 taxable income, gross tax EUR 5,703.99, Guyane reduction EUR 2,281.596 and EUR 3,422 rounded tax. Actual expenses save EUR 540 income tax here, subject to evidence; do not apply both deductions. Different reimbursements or disallowed/private costs can reverse the choice. Brochure pp.107-111; CGI art.197.

name: Actual versus standard employee expenses, 2025 income assessed in 2026
inputs:
  salary: 50000
  actual_expenses: 8000
steps:
  - standard_net: salary - salary * 0.10
  - actual_net: salary - actual_expenses
  - standard_gross: (29579 - 11600) * 0.11 + (standard_net - 29579) * 0.30
  - actual_gross: (29579 - 11600) * 0.11 + (actual_net - 29579) * 0.30
  - standard_after: standard_gross - min(4050, standard_gross * 0.40)
  - actual_after: actual_gross - min(4050, actual_gross * 0.40)
  - standard_tax: round(standard_after - min(standard_after, max(0, 897 - standard_after * 0.4525)), 0)
  - actual_tax: round(actual_after - min(actual_after, max(0, 897 - actual_after * 0.4525)), 0)
  - saving: standard_tax - actual_tax
expected:
  standard_net: 45000
  actual_net: 42000
  standard_tax: 3962
  actual_tax: 3422
  saving: 540

Ask the client first

• What is the income year, actual residence and treaty status, and every move date/address?
• Who belongs to the household, with what marriage/PACS, children, custody, disability or other special-part facts?
• What income, foreign receipts, employer benefits/reimbursements, bank statements and withholding certificates support each category?
• Which micro/actual/flat-payment elections exist, and what prior turnover, loss schedules, property history and ZFANG evidence apply?
• Which documented expenses, maintenance, retirement ceilings, reliefs and foreign-tax credits are being claimed, and what tax was already paid?
• What returns/notices were filed, received or left overdue, including business and foreign-account annexes?

Sources

Source and actual reading scope	URL	Read on
CGI article 4 B, residence and treaty override, read in full	https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000051202565/	2026-11-11
CGI article 197 I and commencement, read for all bands, quotient caps, DOM reduction and décote	https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000006308332/	2026-11-11
DGFiP DOM guidance, read for IR territorial scope and domicile/move reduction rules	https://www.impots.gouv.fr/professionnel/impots-professionnels-dom	2026-11-11
DGFiP 2026 brochure, read for reproduced 2042/C-PRO forms, household pp.75-84 and 369-372, salary pp.107-111, pension deduction, investment/rental/business losses, global charges pp.227-236 and social levies pp.61-63 and common household reliefs pp.237-247; not every specialist chapter	https://www.impots.gouv.fr/www2/fichiers/documentation/brochure/ir_2026/pdf_integral/Brochure-IR-2026.pdf	2026-11-11
BOI-BAREME-000044, current 19 August 2026, read for parts I-III ordinary BIC, BA and BNC thresholds	https://bofip.impots.gouv.fr/bofip/14069-PGP.html	2026-11-11
DGFiP independent professionals, read for micro allowances, results forms and annual workflow; its thresholds concern 2025, not the 2026 regime	https://www.impots.gouv.fr/particulier/professions-independantes	2026-11-11
DGFiP rental guidance, read for micro/real options, deductible costs, deficit and continued-letting rules	https://www.impots.gouv.fr/particulier/location-vide-de-meubles	2026-11-11
2026 2044 instructions, read for ordinary rental charges and deficit attribution	https://www.impots.gouv.fr/sites/default/files/formulaires/2044/2026/2044_5486.pdf	2026-11-11
BOI-IR-BASE-10-20, read for §1 general loss offset and six-year carry-forward	https://bofip.impots.gouv.fr/bofip/6451-PGP.html	2026-11-11
BOI-BNC-BASE-60, read for professional/global and non-professional ringfenced deficits	https://bofip.impots.gouv.fr/bofip/4614-PGP.html	2026-11-11
CGI article 39, read for ordinary expense restrictions used by actual BIC businesses	https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000053542680/	2026-11-11
DGFiP 2026 campaign, read for portal, validation, calendar, PAS and balance reconciliation	https://www.impots.gouv.fr/les-modalites-de-la-declaration-de-revenus-en-2026	2026-11-11
DGFiP results guidance, read for results-return electronic extension and tax forms	https://www.impots.gouv.fr/professionnel/imposition-des-resultats	2026-11-11
Service Public sanctions, read for 2026 late-return percentages, notice period and interest/payment distinction	https://www.service-public.gouv.fr/particuliers/vosdroits/F34175	2026-11-11
BOI-CF-INF-10-30, read for part II personal late-payment surcharge and statutory collection exceptions	https://bofip.impots.gouv.fr/bofip/2428-PGP.html	2026-11-11
BOI-BIC-CHAMP-80-10-85, read for §100 micro eligibility and Guyane/BNC distinction; full business relief in corporate Guide	https://bofip.impots.gouv.fr/bofip/11833-PGP.html	2026-11-11

| CSS articleL136-8, read for I general investment CSG and IV exclusions | https://www.legifrance.gouv.fr/codes/id/LEGISCTA000006173099/ | 2026-11-11 | | LFSS 2026 article 12II, read for different commencement for patrimony assessments and investment receipts | https://www.legifrance.gouv.fr/loda/id/JORFTEXT000053226384/ | 2026-11-11 | | DGFiP securities guidance, read for current income-tax/social components, global election and 2CK prepayment credit | https://www.impots.gouv.fr/particulier/questions/jai-des-valeurs-mobilieres-comment-sont-elles-imposees | 2026-11-11 | | DGFiP rental social levies, read for property/furnished distinction, social-affiliation exception and 6DE deduction | https://www.impots.gouv.fr/particulier/questions/je-donne-un-bien-en-location-dois-je-payer-des-prelevements-sociaux | 2026-11-11 | | Service Public investment social levies, read for resident rates, product/date exceptions, payment and exempt savings | https://www.service-public.gouv.fr/particuliers/vosdroits/F2329 | 2026-11-11 | | CGI article 1758A and 1729, read for ordinary inaccurate IR, correction exceptions and deliberate/fraud sanctions | https://www.legifrance.gouv.fr/codes/id/LEGISCTA000006147258/ and https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000020051904/ | 2026-11-11 |

| DGFiP14October 2026 option conditions, read for micro-tax eligibility,RFR 2024 and election deadline | https://www.impots.gouv.fr/professionnel/questions/en-tant-que-micro-entrepreneur-sous-quelles-conditions-puis-je-opter-pour-l | 2026-11-11 | | DGFiP micro declaration, read for ordinary tax-only percentages and5TA/5TB/5TE fields; dated 2023 social table not used | https://www.impots.gouv.fr/particulier/questions/comment-declarer-les-revenus-provenant-de-mon-activite-dauto-entrepreneur | 2026-11-11 |

| CGI article163quatervicies, read for I-2 ceiling, pooling and five-year rule | https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000053542827/ | 2026-11-11 | | BOI-IR-BASE-20-50-30 current10August 2026, read for §§30-80 age70 rule and exact 2026-31 transition overriding older brochure | https://bofip.impots.gouv.fr/bofip/1117-PGP.html | 2026-11-11 |

| CGI arts.200, 199 sexdecies, 200 quater B and 200-0 A, read for donation rates/carry, home-service and childcare credits and global limits | https://www.legifrance.gouv.fr/codes/id/LEGIARTI000042159351; https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000054251333/2026-06-14; https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000051213135/2025-06-30; https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000053543258/2026-06-25 | 2026-11-11 | | BOI-IR-RICI-250-30 current6July2026, read §§1-35/90-150 for donation date split, excess gifts and imputation; BOI-IR-RICI-150-20 current12August2026, read §§1-190/220/340-350 for home-service base/ceilings/refund/evidence | https://bofip.impots.gouv.fr/bofip/5873-PGP.html; https://bofip.impots.gouv.fr/bofip/3968-PGP.html | 2026-11-11 | | DGFiP household relief pages, read for 2026 reporting fields, actual-cost subsidy adjustments, childcare age and daily maintenance-cost amount | https://www.impots.gouv.fr/particulier/questions/jai-fait-des-dons-une-association-que-puis-je-deduire; https://www.impots.gouv.fr/particulier/emploi-domicile; https://www.impots.gouv.fr/particulier/questions/je-fais-garder-mon-jeune-enfant-lexterieur-du-domicile-que-puis-je-deduire | 2026-11-11 |

Not yet confirmed: the future 2027 assessment's indexed salary/pension limits, final IR bands, issued forms and administrative filing dates for 2026 income; specialist high-income, investment-incentive and disposal computations are outside this ordinary-income Guide.