You landed at Lyon, Toulouse or the Eurostar terminal at Gare du Nord with a visa in your passport, a rental contract in your bag and a clear plan: this is the year you become French for tax purposes. Then spring arrives, neighbours start talking about la déclaration, and a cold realisation follows. Nobody in Britain ever asked you to list every bank account you hold in the world, to split one calendar year between two tax systems, or to file a paper return to an office you have never visited. France asks all three, in French, on fixed deadlines, with fines attached. The good news is that the first French tax return of a British newcomer follows a well-trodden path: paper form 2042 to the tax office of your new home, foreign income on form 2047, every British account on form 3916, and the 2008 France-United Kingdom double tax treaty standing behind you so the same pound of income is not taxed twice. The bad news is that each step has a trap — the wrong form for the months before you moved, the forgotten ISA on the 3916, the British tax year that ends on 5 April while France counts to 31 December — and traps cost money. This guide walks through the whole first return in order: when you actually become taxable in France, what to file and where, how the bill is worked out, and how to challenge it when France and Britain both claim the same income.

I. Becoming taxable in France and filing your first return

A. The move that makes France your tax home, and what London still claims

Everything starts with one question: on which date did you acquire a French domicile fiscal, the tax home that decides whether France taxes your worldwide income or only your French-source income? Article 4 A of the French Tax Code (Code général des impôts) draws the line in one sentence: “Les personnes qui ont en France leur domicile fiscal sont passibles de l’impôt sur le revenu en raison de l’ensemble de leurs revenus. Celles dont le domicile fiscal est situé hors de France sont passibles de cet impôt en raison de leurs seuls revenus de source française.” In plain terms, French tax home means worldwide taxation, and no French tax home means France taxes only French-source income. The full text is freely consultable at article 4 A of the Tax Code on Légifrance.

Three alternative tests in article 4 B decide the matter, and meeting any single one is enough: “Les personnes qui ont en France leur foyer ou le lieu de leur séjour principal”. That is the home test most British movers satisfy first — foyer meaning the household, where your family permanently lives, and séjour principal meaning the place where you spend most of your time, generally more than 183 days in the year. The two other tests catch professional life and money: working in France otherwise than incidentally, and having the centre of your economic interests in France. Read the three tests together at article 4 B of the Tax Code on Légifrance. For a British family that rents or buys in France, enrols children at the local school and lives there day to day, the analysis rarely takes long: the tax home moved with the suitcases.

The subtle point, and the one that generates most double-tax bills, is that Britain may consider you still resident under its own Statutory Residence Test for the same year. Two States, two residence rules, one taxpayer: that overlap is exactly what the 2008 France-United Kingdom double tax treaty exists to resolve. Article 4 B itself defers to it: “Les personnes qui satisfont à l’un au moins des critères fixés aux a à c du présent 1 ne peuvent toutefois pas être considérées comme ayant leur domicile fiscal en France lorsque, par application des conventions internationales relatives aux doubles impositions, elles ne sont pas regardées comme résidentes de France” (see article 4 B of the Tax Code on Légifrance). The treaty’s tie-breaker examines, in strict order, where you have a permanent home, where your personal and economic relations are closest, where you habitually stay, and finally nationality — and the loser State steps back. Because the tie-breaker decides which country taxes what, it deserves its own full treatment, and our companion guide works through it step by step with the forms HMRC and the French administration each expect: Claimed as Tax Resident in Both France and the UK After Brexit: the Tie-Breaker That Decides, and How to Challenge Double Tax. If your arrival year straddles both systems, read that guide alongside this one.

On the British side of the departure, do not leave without telling HM Revenue and Customs. The British guidance is blunt: you must tell HMRC when you are “leaving the UK to live abroad permanently”, so that it can work out whether a refund is due, advise whether tax is payable in more than one country, and set the right treatment for any pension — see Tax if you leave the UK to live abroad on GOV.UK. The procedure depends on your British filing position. If you do not usually file a Self Assessment return, “You need to fill in form P85”, attaching parts 2 and 3 of your P45 where you have one — see form P85 guidance on GOV.UK. If you do file Self Assessment returns, you declare the departure through the residence section, form SA109, which must be sent by post because HMRC’s online service cannot record a departure — see form SA109 on GOV.UK — and the paper deadline is 31 October. Leavers should also check split-year treatment, which can make you non-resident from the day after departure rather than only from the next 6 April: the residence rules are summarised at UK residence and tax on foreign income on GOV.UK. A filed P85 or SA109 is your proof, months later, that Britain released you — keep a copy for the French file too, because the French inspector may ask what London decided.

One calendar mismatch poisons more first returns than any other: the British tax year runs from 6 April to 5 April, while the French return covers 1 January to 31 December. Your P60, your P45 and your British payslips all speak April-to-April; your French 2042 wants January-to-December. Reconcile the two before you start typing numbers: ask your former British employer or pension payer for pay and tax figures covering 6 April to 31 December of the arrival year, convert pounds to euros at the rate the French administration accepts for the year, and keep the monthly payslips so every figure traces back to a document. The exchange-rate line and the April-to-December reconciliation are the two calculations inspectors check first, and a file that shows its workings survives questions that a file of bare totals does not.

B. Your first French return is on paper: forms 2042, 2047 and the 3916 that Britons forget

The legal duty to file is stated without ambiguity in article 170 of the Tax Code: “En vue de l’établissement de l’impôt sur le revenu, toute personne imposable audit impôt est tenue de souscrire et de faire parvenir à l’administration une déclaration détaillée de ses revenus et bénéfices, de ses charges de famille et des autres éléments nécessaires au calcul de l’impôt sur le revenu” — see article 170 of the Tax Code on Légifrance. For a newcomer’s first return, the practical shock is the medium: the French tax administration states that anyone declaring income or wealth in France for the first time has no access to online filing and must complete a paper return. No online account exists for you yet, so the first return travels on paper to the Service des impôts des particuliers (SIP, the local personal tax office) of your new French home — see the administration’s newcomer guidance at impots.gouv.fr: arriving or returning to France. Download form 2042 from impots.gouv.fr, complete it by hand or on screen before printing, sign it, and post it or deliver it to that office. The campaign calendar matters: the paper deadline arrives first, roughly in the third week of May, while online filers by residential zone get extra days into June — so check the year’s dates on impots.gouv.fr the moment the campaign opens and diary the paper date, because a newcomer cannot switch to the online deadline at the last minute. Late filing draws a 10 percent increase for simple delay, rising where a formal notice goes unanswered, so the paper return should leave your hands a full week before the deadline.

What the 2042 must contain depends on whether France taxed you before you moved. The common British case — no French obligations while living in Britain — is straightforward: newcomers with no prior French obligations must report all income received between the date of arrival and 31 December, adding the relevant annexes for their income — the 2044 for French rental income, the 2047 for income received abroad, and similar schedules where needed. Only income from the arrival date to 31 December goes on the return; pre-arrival British income stays out. The second case is the split return. If you owned a French rental or otherwise had French-source income taxable in France before the move, you previously belonged to the non-residents’ tax office, and the arrival year is cut in two: French-source income taxable in France and received between 1 January and the move goes on a 2042-NR, while all income received after the move goes on a standard 2042. You are then taxed as a non-resident for January to the move and as a resident afterwards — and the 2042-NR goes to the non-residents’ office while the 2042 goes to your new local office. British owners who let a French flat before relocating fall squarely in this second case; our landlord guide details how that rental income is treated once you are resident: British Landlord Living in France After Brexit: Who Taxes Your UK Rental Income, How to Declare It on Forms 2047 and 2042, and How to Challenge Double Tax and Social Charges.

Form 2047, the return for income received abroad, is where most British newcomers live for pages at a time. British salary for months worked partly from France, UK rental income from the house you have not yet sold, dividends from a British brokerage account, interest from savings: each category has its box, and the form computes the French tax before the treaty credit washes out what Britain was entitled to tax. Report gross amounts, convert each receipt or use the annual average rate consistently, and attach the 2047 to the 2042 — the two travel together. British pensions need the same care: State Pension and most private pensions follow the treaty allocation between the two States, while certain government-service pensions remain taxable only in Britain, so identify each pension’s nature before writing a single figure. Where the treaty gives the taxing right to the United Kingdom, France still wants the income on the return and then grants the eliminating credit; leaving treaty-taxed income off the 2047 because “Britain already taxed it” is the single most frequent newcomer error, and it produces exactly the reassessment the treaty was meant to prevent.

Then comes the form Britons almost never expect: the 3916, the declaration of accounts opened, held, used or closed abroad. Article 1649 A of the Tax Code imposes it in these terms: “Les personnes physiques, les associations, les sociétés n’ayant pas la forme commerciale, domiciliées ou établies en France, sont tenues de déclarer, en même temps que leur déclaration de revenus ou de résultats, les références des comptes ouverts, détenus, utilisés ou clos à l’étranger.” — see article 1649 A of the Tax Code on Légifrance. Every British current account, savings account, cash ISA, stocks-and-shares ISA dealing account, and any account you closed during the year must appear with the bank’s references; the ISA wrapper changes nothing, because the account itself sits with a British institution outside France. The official service-public guidance lists who must file and what happens otherwise at Declaring accounts opened abroad on service-public.fr, and the penalties are fixed per account: a flat fine of EUR 1,500 per undeclared account, rising to EUR 10,000 where the account sits in a State that has not concluded an anti-fraud agreement with France — Britain has such an agreement, so the standard exposure is EUR 1,500 per account — plus an 80 percent increase of the duties on the sums in undeclared accounts, which then replaces the flat fine. Three forgotten British accounts therefore cost €4,500 before any tax is even discussed, and the fine lands per account per year. File one 3916 per account, every year, even for the dormant savings account with £200 in it; the compliant newcomer lists everything in year one and simply carries the list forward.

Two companion annexes complete the picture for many British files. Form 2044 carries French rental income for owners who let before or after the move, with the micro-foncier simplification below the threshold and the full régime réel above it. And residents keeping interests abroad should read the administration’s dedicated page for their ongoing duties at impots.gouv.fr: resident of France with interests abroad. Before sealing the envelope, run the newcomer’s checklist: 2042 signed and dated, 2047 attached with every British receipt converted, 2044 if there is French rental income, one 3916 per British account open, used or closed in the year, a copy of everything kept at home, and proof of posting. The first return is also your application for a tax number (numéro fiscal): once processed, it opens your online personal space (espace particulier) and every later return, payment and claim flows through it.

II. Paying the right amount and challenging the bill when both countries claim it

A. How France prices your household: joint taxation, the family quotient and the withholding gap

France does not tax individuals in isolation; it taxes the household (foyer fiscal). Article 6 of the Tax Code provides that “Sauf application des dispositions du 4 et du second alinéa du 5, les personnes mariées sont soumises à une imposition commune pour les revenus perçus par chacune d’elles et ceux de leurs enfants et des personnes à charge mentionnés au premier alinéa ; cette imposition est établie aux noms des époux.” — see article 6 of the Tax Code on Légifrance. A married British couple arriving together therefore files one joint 2042 in both names, pooling both spouses’ worldwide income from the arrival date; partners in a civil partnership (pacte civil de solidarité, PACS) are taxed jointly in the same way, while unmarried partners without a PACS file separately. The arrival year can split a household in time as well as in composition: where one spouse moves in March and the other follows in September, each spouse’s pre-arrival income stays out and only post-arrival income enters the joint return, so keep dated proof of each person’s move — tenancy start, travel records, employer letters — because the inspector cannot apply the cut-off without them.

The pooled income is then divided into parts under the family quotient (quotient familial): broadly one part per adult and a half-part per child, with the resulting figure run through the progressive scale and multiplied back up. Article 197 states the mechanism: “L’impôt est calculé en appliquant à la fraction de chaque part de revenu qui excède 11 600 € le taux de : – 11 % pour la fraction supérieure à 11 600 € et inférieure ou égale à 29 579 € ; – 30 % pour la fraction supérieure à 29 579 € et inférieure ou égale à 84 577 €” — see article 197 of the Tax Code on Légifrance, which continues through 41 and 45 percent bands and caps the quotient advantage per half-part. Two consequences follow for newcomers. First, always verify the scale printed on the year’s return, because the thresholds move annually and last year’s planner found online may already be out of date. Second, declare the children correctly: resident children count for the quotient from the arrival date, and the extra half-parts routinely save a young family more than any other line on the return. Add the treaty layer on top: income that the treaty reserves to Britain is still declared, then neutralised by a tax credit (crédit d’impôt) equal to the French tax on that income, so the effective French charge on doubly-claimed income falls to zero but only where the 2047 carried it in the first place. Social charges (prélèvements sociaux) follow their own allocation and are not creditable in the same way, which is why the bottom line on the avis d’imposition (the tax assessment notice) sometimes surprises Britons who expected the treaty to erase everything.

The arrival year also creates a cash-flow trap built into the withholding system (prélèvement à la source). Article 204 A of the Tax Code lays down the principle that wages, pensions, annuities, commercial, agricultural and non-commercial profits and rental income give rise, in the year the taxpayer receives or realises them, to a contemporaneous levy — see article 204 A of the Tax Code on Légifrance. In practice the levy takes two forms — deduction at source by the payer for salaries and pensions, and instalments (acomptes contemporains) paid directly by the taxpayer for other income — and “Le prélèvement effectué par le débiteur ou acquitté par le contribuable s’impute sur l’impôt sur le revenu dû par ce dernier au titre de l’année au cours de laquelle il a été effectué. S’il excède l’impôt dû, l’excédent est restitué.” The newcomer problem is timing: in your arrival year almost nothing was withheld, because no French payer knew you and no instalment plan existed, so the first avis d’imposition arrives with a full balancing payment (solde) and no credit against it. Budget for that solde from the day you move — a year of French tax paid in one autumn bill — and set up monthly instalments or an updated withholding rate in your new online space the moment it opens, so year two is collected as you earn. Where Britain withheld tax on the same income, the treaty credit on the French side and any HMRC repayment on the British side each follow their own timetable; neither administration waits for the other, so file both claims promptly rather than holding one back.

B. Challenging the assessment: the reclamation, the evidence bundle and the two-month court clock

When the avis d’imposition lands and the figure is wrong — worldwide income demanded where only French-source income was due, treaty credit refused, pre-arrival months included, 3916 fines stacked per account — the remedy is the contentious claim (réclamation contentieuse), filed first with the administration, not with a judge. The admissibility deadline is generous but absolute. Article R*196-1 of the Tax Procedure Book (Livre des procédures fiscales) requires that “Pour être recevables, les réclamations relatives aux impôts autres que les impôts directs locaux et les taxes annexes à ces impôts, doivent être présentées à l’administration au plus tard le 31 décembre de la deuxième année suivant celle, selon le cas : a) De la mise en recouvrement du rôle ou de la notification d’un avis de mise en recouvrement” — see article R*196-1 of the Tax Procedure Book on Légifrance. For income tax assessed by rôle, that means 31 December of the second year after the assessment year: an assessment issued in 2026 can be challenged until 31 December 2028. File through the secure messaging of your online personal space where possible, or by recorded-delivery letter to the office that issued the notice, and state precisely what you seek — discharge (dégrèvement) of a sum, reduction, or restitution — with the legal basis attached. The administration has six months to answer; silence for six months counts as an implied rejection and opens the road to court.

What wins a newcomer’s reclamation is rarely rhetoric and almost always paper. Assemble the file as the inspector will read it: proof of the arrival date and of each spouse’s arrival where they differ, the British P85 or SA109 showing HMRC recorded the departure, the April-to-December reconciliation with payslips and the exchange-rate source, the treaty analysis box by box linking each item of income to the 2047 line that carried it, and copies of every 3916 filed. The four recurring winning arguments are worth memorising. First, the cut-off: income received before the French tax home existed cannot enter the 2042, and bank statements dated before the move prove it. Second, the 2042-NR boundary: where pre-move French-source income was wrongly swept into the resident return instead of the non-resident one, the assessment misapplies the administration’s own split-year rule described above. Third, the treaty credit: where British-taxed income was declared on the 2047 and the credit was denied or miscalculated, the reclamation recomputes it line by line. Fourth, the 3916 fines: accounts closed before the move, accounts with no funds, or duplicates filed in good faith each support reduction or discharge of the flat penalties. Where the administration concedes nothing, the dispute moves to the administrative court (tribunal administratif) of your home, and the clock there is short: “La juridiction ne peut être saisie que par voie de recours formé contre une décision, et ce, dans les deux mois à partir de la notification ou de la publication de la décision attaquée.” — see article R421-1 of the Administrative Justice Code on Légifrance. Two months from the express rejection, or from the six-month silence, not a day more: diary the date the moment you file the reclamation, because a perfect case filed on day sixty-one is a lost case.

Conclusion

The first French tax return rewards the British newcomer who treats it as a project, not a formality. Fix the date France became your tax home under articles 4 A and 4 B, tell HMRC you have left through a P85 or SA109, and reconcile April-to-April Britain with January-to-December France before writing any figure. File the paper 2042 with the local office of your new home, carry every British receipt on the 2047, split the arrival year with a 2042-NR where pre-move French income requires it, and declare every British account on a 3916 — the EUR 1,500-per-account fine is the most expensive line a newcomer ever signs. Price the household through joint taxation and the family quotient, expect the first autumn’s balancing payment with no withholding behind it, and set up instalments for year two. And where the assessment overreaches, challenge it in the order the law prescribes: reclamation before 31 December of the second year, evidence bundle first, administrative court within two months of refusal. Handled this way, the arrival year closes cleanly: Britain releases you, France counts you correctly, the treaty does the job it was written to do, and the second return — filed online, in minutes — feels like the reward it is.

Need a quick opinion on your case?

If you are British and have just moved to France, or an assessment, a 3916 fine or a double-tax bill has just arrived, speak to a lawyer (avocat) before the deadline expires. Our initial telephone consultation, 80 EUR incl. VAT, gives you a clear answer on your file within 48 hours. Call +33 6 46 60 58 22 (Maître Reda Kohen) or write via our contact page.