The French tax return is not one big job. It's three smaller ones. Break it down correctly and it becomes manageable — here's how.
Most UK expats approach the French tax return as a single enormous task. That's what makes it feel overwhelming. It isn't one task — it's three, done in the right order.
Plan before you touch the portal. Map your income to the right forms before you start entering figures. Then File — and know that even after you submit, you can correct it.
Each step is covered below. Where there's a deeper article on a topic, we link to it — this guide is the overview, not the detail.
Step 1 — Plan
Planning happens before you open impots.gouv.fr. These are the decisions and checks that, if left until you're inside the portal, will either slow you down or send you in the wrong direction.
Check your deadline first. France staggers its deadlines by department. Online filing opened on 9 April 2026 for the 2025 tax year.
| Zone | Departments | Deadline |
|---|---|---|
| Zone 1 | 01–19 (and non-residents) | Thursday 21 May 2026 |
| Zone 2 | 20–54 (including Corsica) | Thursday 28 May 2026 |
| Zone 3 | 55–976 | Thursday 4 June 2026 |
If you live in France, your deadline is based on your department. UK non-residents — those still living in the UK but with French-source income — fall into Zone 1 and have the earliest deadline.
Establish your tax residency. France decides whether you're a French tax resident — you don't. If you are resident, you declare your worldwide income here. If you're not sure, read this before you file: French Tax Residency: The Rules, the Myths and What Actually Decides Where You Pay Tax.
Know how France taxes your household. France taxes the household as a single unit, not individuals. A married couple is taxed jointly. The total income is divided by the number of "shares" in the household before the tax rate is applied — which is why French income tax often comes out lower than people expect. This is called the quotient familial. The quotient familial explained →
Decide on your S1 status. If you receive a UK State Pension and live in France, you almost certainly qualify for an S1 certificate. This can eliminate social charges on your pension income entirely and reduce them significantly on investment and rental income. The decision to claim it must be made before you file — it isn't applied automatically. S1 explained: what it is, who gets one, and why it matters →
Think about the flat tax vs sliding scale. If you have investment income — dividends, interest, capital gains — you have a choice about how it's taxed. The default flat rate is 31.4%. If your overall income is modest, the sliding scale may produce a lower bill. This choice is made by ticking box 2OP on your return and applies to all your investment income for the year — you can't apply it to just one type. Decide before you start. PFU vs progressive tax: which is better for your investment income? →
Note any lump sums. If you received a large one-off sum — a pension lump sum, an inheritance, proceeds from a property sale — special rules may apply, including the quotient system which can significantly reduce the tax due. Pension lump sums in France: tax treatment and the quotient system →
Make sure you can log in. Check your numéro fiscal and your impots.gouv.fr password are working before the deadline. Recovering access under time pressure is stressful and avoidable.
Step 2 — Map
Mapping means knowing which income goes on which form before you start entering figures. Most errors on French tax returns happen because people go straight to the portal and try to work it out as they go.
France uses a main return (Form 2042) and a series of supplementary forms. For UK expats, the most important supplementary form is Form 2047 — the foreign income annex. You complete the supplementary forms first; they then feed figures into the main return.
Here's how the most common UK income types map:
UK State Pension and UK private pension Both declared on Form 2047 Section 1, Line 12. Transferred to Box 1AM (Declarant 1) or Box 1BM (Declarant 2) on Form 2042. Taxed in France under the treaty. UK State Pension in France → | UK Private Pension in France →
UK Government Service Pension Civil service, armed forces, police, fire service. Declared on Form 2047 but exempt from French income tax — goes via Box 8TK on Form 2042 to claim the treaty exemption. Taxed only in the UK. Note: NHS and Teachers Pensions do not qualify. UK Government Service Pension in France →
UK rental income Declared on Form 2047. Exempt from French income tax under the treaty, but included in the calculation that determines your overall French tax rate. Social charges apply. UK rental income: how to declare it as a French resident →
UK dividends and interest Declared on Form 2047 Section 2. Transferred to the relevant boxes on Form 2042. Subject to income tax (flat rate or sliding scale) and social charges. UK dividends and interest: how to declare them in France →
ISAs and SIPPs France does not recognise the ISA wrapper. Income inside an ISA is taxable in France. A SIPP is treated as a private pension. Both require annual declaration on Form 3916 as foreign financial accounts. ISAs and SIPPs: French tax treatment →
Foreign bank accounts Every account held outside France — including UK bank accounts, ISAs, and digital accounts — must be declared annually on Form 3916, regardless of balance or whether income was received. The penalty for missing this is €1,500 per account per year.
Currency conversion. Every figure on your French return must be in euros. The correct approach is to use the Banque de France rate on the date each payment was received. For recurring income like pensions, the annual average rate is permitted. Converting a year's worth of UK income manually — 13 pension payments, multiple dividend payments, rental income — is time-consuming and easy to get wrong. Taxpert's filing assistant applies the correct rate to each transaction automatically.
What exchange rate do I use for my French tax return? →
Step 3 — File
Once you've planned your decisions and mapped your income, the filing process itself follows four stages inside impots.gouv.fr:
- Household — verify your personal details and marital status
- Main return (Form 2042) — the core of the declaration
- Supplementary forms — this is where you complete Form 2047 for UK income, Form 3916 for foreign accounts, and any other annexes
- Summary and signature — a final simulated calculation before you submit
One important point: you often can't complete the main return before the supplementary forms. Go to the annexes first, complete Form 2047, and the figures will transfer automatically to Form 2042. Always check that the transfer has happened correctly before submitting.
Filing online is mandatory for most people. Paper filing is permitted only in exceptional circumstances — for example, if you have no internet access. Paper vs online filing in France: which applies to you? →
If you miss the deadline — file anyway, as soon as possible. A late return triggers a 10% surcharge on your tax bill, rising to 40% if formal reminders are ignored. Filing late is significantly better than not filing at all.
You can correct your return after filing. The DGFiP opens a correction window after the official deadline — usually in late July — where you can amend your return online without formal appeal. If you're unsure about something, file what you have by the deadline and correct it later. You can also leave a message at the end of the filing process to flag a specific point to the tax office — this keeps you transparent and compliant while resolving uncertainties.
The two-tier bill: don't be surprised
One thing that catches many UK expats off guard: the French tax return produces two separate bills, not one.
The first is income tax — calculated on the progressive scale after household shares, generally lower than people expect.
The second is social charges — a separate set of levies on top of income tax, up to 18.6% on investment income and up to 9.1% on pension income. These fund the French healthcare and benefits system. Even if your income tax bill is low or zero, you may still owe social charges.
If you hold an S1 certificate, your social charges are significantly reduced — or eliminated on pension income. Without one, the full rate applies.
See the social charges rates by income type on the Taxpert reference data page →
Social charges explained: what they are and how they affect UK expats →
Frequently Asked Questions
When is the French tax return deadline in 2026?
It depends on your department. Zone 1 (departments 01–19 and non-residents) closed on 21 May 2026. Zone 2 (20–54) on 28 May 2026. Zone 3 (55–976) on 4 June 2026. Online filing opened on 9 April 2026.
Do I need to declare my UK income on a French tax return?
Yes, if you are a French tax resident. France taxes worldwide income. Which country actually taxes each type of income depends on the UK-France tax treaty — but even income taxed in the UK must usually be declared in France to determine your overall tax rate.
What is Form 2047 and do I need it?
Form 2047 is the foreign income annex — the form where UK expats declare income from outside France. If you have any UK income (pension, rental, dividends, interest), you need it. Complete it before the main return (Form 2042) — figures from 2047 transfer to 2042 automatically.
Do I need to declare my UK bank accounts?
Yes. Every account held outside France must be declared annually on Form 3916 — including UK bank accounts, ISAs, and digital accounts. This applies regardless of the balance or whether you received any income. The penalty for failing to declare is €1,500 per account per year.
What happens if I file late?
A late return triggers a 10% surcharge on your tax bill, rising to 40% if formal reminders are ignored. File as soon as possible — late is significantly better than not filing at all.
Can I correct my return after submitting it?
Yes. The DGFiP provides an online correction window after the official deadline, usually opening in late July. You can amend your return without formal appeal during this period. If you're uncertain about something, file what you have by the deadline and correct it later.
What exchange rate do I use to convert my UK income to euros?
The technically correct approach is the Banque de France rate on the date each payment was received. For recurring income like pensions, the annual average rate is permitted. Full guide to exchange rates →