You sold the house in Surrey in September, signed the compromis on the stone house near Sarlat in October, and spent Christmas between two countries with suitcases still half unpacked. Then spring arrives in France, the neighbours start talking about their déclaration de revenus (the yearly income tax return), and the awkward question lands: do you, a Briton who only arrived a few months ago, really have to file a French tax return this year? And if both London and Paris claim you as their taxpayer, who decides, and what do you do when the first French bill looks wrong?

This guide answers those questions for the British newcomer in France after Brexit. It explains when you become French tax resident under the three alternative tests of the Tax Code, which forms your first filing needs and when the campaign opens, what late filing costs and why a tax office can refuse to register your return, and how to strip out double tax on British-source income and challenge an assessment step by step. Every decisive rule below is quoted word for word from a statute, a treaty or a judgment checked for this article, with its official link beside it. French terms are translated at first use, and the courtroom examples use the figures the judges themselves decided.

I. Are you French tax resident, and must you file a return in your first year?

A. Am I tax resident in France? The three alternative tests of Article 4 B

French tax residence (domicile fiscal) is the doorway to everything: worldwide taxation, the duty to file, and the treaty protection that follows. Article 4 A of the Code général des impôts states the stakes 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.” In plain English, a French tax resident pays French income tax on worldwide income, while a non-resident pays only on French-source income: “Celles dont le domicile fiscal est situé hors de France sont passibles de cet impôt en raison de leurs seuls revenus de source française.”

Whether you hold that residence is answered by Article 4 B of the same Code, and the structure matters enormously for newcomers. The three tests are alternative, not cumulative: “Sont considérées comme ayant leur domicile fiscal en France au sens de l’article 4 A : a. Les personnes qui ont en France leur foyer ou le lieu de leur séjour principal ; b. Celles qui exercent en France une activité professionnelle, salariée ou non, à moins qu’elles ne justifient que cette activité y est exercée à titre accessoire ;” The third test catches those whose centre of economic interests sits in France: “c. Celles qui ont en France le centre de leurs intérêts économiques.” Meeting any one of the three is enough; failing two of them saves you only if you fail the third as well.

For most British arrivals, the fight happens on the first test, the foyer (the home where you normally live and centre your personal life). The Administrative Court of Appeal of Paris gave that word a definition every newcomer should memorise. In a 20 October 2023 judgment concerning a taxpayer who split his year between Paris and Israel, the court held: “Pour l’application des dispositions du a du 1 de l’article 4 B du code général des impôts, telles qu’éclairées par les travaux préparatoires de la loi n° 76-1234 du 29 décembre 1976 d’où elles sont issues, le foyer d’un contribuable célibataire, sans charge de famille, s’entend du lieu où il habite normalement et a le centre de sa vie personnelle, sans qu’il soit tenu compte des séjours effectués temporairement ailleurs en raison des nécessités de la profession ou de circonstances exceptionnelles.” Read the full reasoning in CAA Paris, 20 October 2023, No. 22PA00816. The home that counts is where you normally live and centre your personal life, ignoring temporary stays elsewhere for work or exceptional circumstances.

Day-counting alone does not settle it, and the same judgment proves the point brutally. The taxpayer had spent only 164 days in France against 201 in Israel, yet the court found: although he had spent only 164 days in France in 2015 against 201 days in Israel, he kept in France a habitual residence of a permanent nature which he occupied normally. What tipped the balance was permanence, not arithmetic: a Paris flat kept all year with a cleaner on the payroll, post delivered there, matching electricity and gas consumption, family ties in France, and French bank accounts receiving pension income. The conclusion followed: the court therefore treated him as having kept the centre of his personal interests in France, where he normally lived, and hence his foyer there within Article 4 B for 2015. For the British newcomer, the lesson is practical. Keep the French house available year-round, move the post, the doctor, the children’s schooling and the daily spending to France, and the administration will call that your foyer even in a year when you slept more nights in Britain. Conversely, a genuinely temporary pied-à-terre occupied between two longer stays elsewhere, with no permanence and no personal centre, points the other way — but expect the tax office to test that story against utility bills, bank statements and school certificates, exactly as it did in Paris.

The second test bites the remote worker: carrying on a professional activity in France is enough unless you prove it is merely accessory. A Briton who moves to the Dordogne but keeps working full-time for a London employer from a French desk needs advice on this test specifically, because the administration reads “activité à titre accessoire” (merely secondary activity) narrowly. The third test, the centre of economic interests, catches the investor whose life looks French even if the diary looks mixed: French bank accounts receiving pensions and funding daily life, shares in French companies, a French property let or managed locally — all of these featured in the Paris judgment above. Map yourself against all three tests in your arrival year, keep the evidence for each, and remember the safety valve built into the statute itself: the same article adds a safety valve: meeting one of these tests still does not make a person French tax resident where a double tax treaty regards that person as not resident in France. If the 2008 France–United Kingdom double tax treaty makes you exclusively British under its tie-breaker, domestic residence falls away — a mechanism explained in detail in our companion guide to dual residence, linked in Part II below.

B. Which return do I file first, and when? Forms 2042 and 2047, online filing and the spring campaign

Once residence is established, the filing duty follows automatically. Article 170 of the Code général des impôts provides: “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”. Note the wording carefully: the duty falls on anyone liable to the tax, not on anyone who has received a form or an invitation. In your arrival year you file in the spring following arrival for the previous calendar year’s income, and you declare the income of the whole household (foyer fiscal) — spouses file one joint return, and the same article adds that “Les époux doivent conjointement signer la déclaration d’ensemble des revenus de leur foyer.” A couple who married or entered a civil partnership before moving files jointly from the first return, which usually changes the bands and the family tax quotient in their favour.

The mechanics surprise many Britons. First, online filing is the rule, not the option. The official service-public information page, verified on 5 June 2026, states: online filing is compulsory wherever the household has internet access. Read the full filing guide on service-public.fr: income tax, yearly return. A newcomer with no previous French tax account creates access on impots.gouv.fr and files through the personal space; the paper form survives only for those who genuinely cannot file online. Second, the much-discussed automatic return (déclaration automatique, where the administration pre-fills everything and silence means consent) is closed to you in year one. The same official page limits it strictly: automatic filing for 2026 income requires two cumulative conditions: having been taxed in 2025 solely on pre-filled income, and having reported no change of circumstances in 2025. A household that did not exist in the French system in 2025 cannot meet the first condition, and a cross-Channel move is the definition of a change of circumstances — so budget an evening to complete the return by hand, line by line.

Which forms? The official page answers directly: depending on the situation, the return to use is form 2042 or 2042 C. Form 2042 is the main return; the complementary 2042 C covers additional income and charges. Two supplements matter to almost every British household. The same guide lists the form 2047 for income received abroad — the statement of income received abroad, where you report British pensions, interest, dividends and any UK rental income before the treaty relief is applied. Our companion guide to British landlords in France walks through forms 2042 and 2047 line by line for UK rental income (see British Landlord Living in France: Who Taxes Your UK Rental Income). Owners of French rental property add form 2044 for unfurnished lettings, and that same official page confirms the form 2044 for rental income from unfurnished lettings. Declare everything first and claim the treaty credit second: as Part II explains, the Conseil d’État rewards the taxpayer who declares British income in the United Kingdom even where no British tax is ultimately paid, and the French return is where that declaration trail begins.

Timing is the yearly trap. The campaign opens each spring for the previous year’s income, and the administration staggers the online deadlines by département while the paper deadline falls earlier. For orientation, the official page records that the 2027 campaign covering 2026 income begins in April 2027. Check the current year’s brochure and your impots.gouv.fr space for the exact dates of your zone as soon as April arrives, because the surcharges for missing them are automatic and the next section shows how heavy they are. One mirror point for the British side of the move: leaving the United Kingdom does not end the story there either. The British government’s residence guidance confirms that when a person moves in or out of the United Kingdom, the tax year is generally divided into a non-resident part and a resident part, adding: “This is called ‘split-year treatment’.” See GOV.UK: UK residence and tax, residence status when you move. You may therefore file a British Self Assessment return with split-year treatment for the departure year while simultaneously filing your first French return — and the same guidance reminds leavers that non-residents pay British tax on their British income only, not on foreign income, while residents are taxed on worldwide income. Keep both filings consistent on dates of departure and arrival: contradictory dates across the Channel are the classic trigger for the double-residence dispute examined in Part II.

II. The bill is wrong: late-filing penalties, refused returns and how to challenge

A. What happens if I file late, and can the tax office really refuse my return?

Missing the spring deadline is expensive even when the return itself shows little or no tax. Article 1728 of the Code général des impôts provides: “Le défaut de production dans les délais prescrits d’une déclaration ou d’un acte comportant l’indication d’éléments à retenir pour l’assiette ou la liquidation de l’impôt entraîne l’application, sur le montant des droits mis à la charge du contribuable ou résultant de la déclaration ou de l’acte déposé tardivement, d’une majoration de : a. 10 % en l’absence de mise en demeure ou en cas de dépôt de la déclaration ou de l’acte dans les trente jours suivant la réception d’une mise en demeure d’avoir à le produire dans ce délai”. Ten per cent applies from the start, with no formal demand needed, and the surcharge bites on the tax itself. Ignore the formal demand (mise en demeure) that follows, and the rate jumps: “40 % lorsque la déclaration ou l’acte n’a pas été déposé dans les trente jours suivant la réception d’une mise en demeure d’avoir à le produire dans ce délai”. Newcomers are the typical victims of the first bracket: the household that assumed year one did not count, or waited for an invitation that never comes, discovers the 10 per cent on the avis d’impôt (the tax bill) in autumn. File late rather than never — the return stops the clock — and challenge the surcharge separately if a genuine obstacle explains the delay.

Less known, and more distressing, is the reverse situation: the tax office (service des impôts des particuliers, the local personal tax office, universally called the SIP) that refuses to register your return at all. This is not theoretical. In CAA Paris, 23 October 2018, No. 18PA00108, a couple had filed a 2014 return showing no taxable income, and the office answered with a decision “refusant d’enregistrer leur déclaration de revenus au titre de l’année 2014”. The stated reason went to the heart of Part I of this guide: “cette déclaration ne donnerait pas lieu à l’établissement d’un avis de non imposition, au motif que les intéressés ne pouvaient pas être considérés comme fiscalement domiciliés en France en 2014”. No recognised domicile, no registration, not even a nil assessment (avis de non-imposition) — yet that very document is the paper newcomers need for visas, school registrations, housing benefit and health cover. The administrative court and then the court of appeal both rejected the couple’s challenge, because on the facts they indeed lacked a French tax domicile that year.

Turn that defeat into a checklist. If the SIP questions your domicile, it will look for exactly the evidence catalogued in the 2023 Paris judgment quoted above: a dwelling kept permanently and occupied normally, post delivered and not redirected, utility consumption consistent with living there, family members nearby, and French bank accounts receiving income and paying daily expenses. Assemble that file before you walk into the SIP or answer its questionnaire: lease or title deeds, electricity and gas bills across the year, home insurance, children’s school certificates, médecin traitant (registered GP) declaration, French bank statements, and proof of the British departure such as the UK council tax closure and shipping inventory. Where the office still refuses registration or issues a manifestly wrong assessment, do not accept a verbal answer. Ask for the refusal or the assessment in writing, with its reasons, because the challenge procedure in the next section runs on written decisions and strict time limits — and on one threshold question the Paris courts already answered, which is whether you were genuinely domiciled at all.

B. How do I remove double tax on British income and challenge a French assessment?

Two battles are often confused, so separate them. The first battle is substantive: making sure British-source income is not taxed twice. The second is procedural: contesting the French bill. Win the first and the second may become unnecessary; lose track of the second while fighting the first and the bill becomes final anyway.

On substance, the starting point is the 2008 France–United Kingdom treaty, signed in London on 19 June 2008 and effective in France since 1 January 2010 (see GOV.UK: 2008 UK–France Double Taxation Convention, in force). Where both countries claim you as resident, Article 4 of that treaty decides through a cascade: the treaty deems the individual resident only of the State where a permanent home is available, or, with a home in both States, of the State of closer personal and economic relations (the centre of vital interests). The full tie-breaker — permanent home, centre of vital interests, habitual abode, nationality, then agreement between the two administrations — is worked through with examples in our dedicated guide (see Claimed as Tax Resident in Both France and the UK: the Tie-Breaker That Decides), which is the reference page of this site’s treaty-residence cluster. Settle residence first, because everything else — which country exempts, which country credits — flows from it.

Once France is confirmed as the residence state, British income declared in France is generally relieved by credit rather than exemption. Article 24 of the treaty provides the French method, and for most ordinary income the credit equals the French tax on that income: for most ordinary income the credit equals the French tax attributable to that income, provided the French resident is subject to United Kingdom tax on it. The Conseil d’État has now told taxpayers exactly what that final condition means, and the answer is generous. In an opinion of 12 February 2020 on the treaty credit for British-source income, the court held: “cette condition n’exige pas que les revenus en cause aient été soumis à une imposition effective.” Read CE, avis, 12 February 2020, No. 435907. No effective British taxation is required. The same opinion completes the rule: “Il résulte de ce qui a été dit au point 6 ci-dessus que la condition prévue à l’alinéa (i) du a) du paragraphe 3 de l’article 24 de la convention doit être regardée comme satisfaite s’il est établi par le résident de France qu’il a déclaré les revenus en cause au Royaume-Uni, parce que ces revenus étaient compris dans la base de l’un des impôts énumérés au a) du 1 de l’article 2 de la convention, alors même qu’il n’aurait acquitté dans cet Etat aucun impôt à raison de ces revenus.” Declare the income in Britain — within the base of a listed British tax — even if allowances or reliefs wipe out the British bill, and the French credit stands. The practical discipline follows: file the British Self Assessment return for the overlapping year, keep the HMRC computation and submission receipt, report the same income on the French form 2047, claim the treaty credit, and attach or hold ready the British proof. The taxpayer who declares on both sides keeps the credit; the taxpayer who hides the income from one side loses it on both.

On procedure, every challenge to a French income tax bill travels the same marked path, and the signposts are statutory. First, the claim (réclamation) goes to the administration before any judge. Article L190 of the Livre des procédures fiscales defines its scope: “Les réclamations relatives aux impôts, contributions, droits, taxes, redevances, soultes et pénalités de toute nature, établis ou recouvrés par les agents de l’administration, relèvent de la juridiction contentieuse lorsqu’elles tendent à obtenir soit la réparation d’erreurs commises dans l’assiette ou le calcul des impositions, soit le bénéfice d’un droit résultant d’une disposition législative ou réglementaire.” A wrong residence finding, a forgotten treaty credit, a miscalculated surcharge — each is either an error in the base or the denial of a statutory right, and each belongs in the réclamation, filed online from the impots.gouv.fr secure messaging or by recorded post to the SIP that issued the bill.

Second, the time limit is forclusionary: miss it and the substance no longer matters. Article R*196-1 of the Livre des procédures fiscales provides: “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”. For an income tax bill collected by rôle (the tax roll) or by online notice, count two full years after the year of collection: a bill issued in autumn 2026 is challengeable until 31 December 2028. Diary that date the day the bill arrives, because courts apply it strictly — the Toulouse court of appeal recently confirmed that only proven ignorance of the assessment, through missing appeal information, can push the starting point back (see CAA Toulouse, 31 December 2025, No. 23TL02834), and counting on that exception is not a strategy.

Third, you need not pay the disputed part while you fight. Article L277 of the Livre des procédures fiscales provides: “Le contribuable qui conteste le bien-fondé ou le montant des impositions mises à sa charge est autorisé, s’il en a expressément formulé la demande dans sa réclamation et précisé le montant ou les bases du dégrèvement auquel il estime avoir droit, à différer le paiement de la partie contestée de ces impositions et des pénalités y afférentes.” Two formalities are essential: ask expressly and quantify the discharge claimed. Do that, and “L’exigibilité de la créance et la prescription de l’action en recouvrement sont suspendues jusqu’à ce qu’une décision définitive ait été prise sur la réclamation soit par l’administration, soit par le tribunal compétent.” Enforcement and recovery limitation freeze until a final decision. Above the amount fixed by decree the accountant may demand guarantees, so large disputes need a bank guarantee arranged in parallel — another reason to quantify early and precisely.

Conclusion

The first French tax return rewards the newcomer who treats residence as a fact to be proved, not a status to be assumed. One of the three Article 4 B tests is enough to make you French tax resident on worldwide income, and the courts will find your foyer in the permanent home, the delivered post and the family life rather than in the day count. File online in the spring after arrival on forms 2042 and 2047, even where no tax seems due; the automatic return is not for you, and the 10 per cent surcharge needs no warning. If the SIP refuses to register you, answer with the evidence of genuine settlement, in writing. If both countries claim you, let the treaty’s centre-of-vital-interests test decide, declare the British income on both sides to keep the French credit the Conseil d’État protects, and challenge any wrong bill by réclamation before 31 December of the second year with an express, quantified request to defer the disputed part. Keep every bill, every filing receipt and every HMRC computation from year one, and the first return becomes what it should be: the foundation of your French tax life, not its first dispute.