You sold up in Manchester, signed the compromis in the Dordogne, enrolled the children at the local collège and finally collected the keys in June. Then two tax offices both claim you. HMRC writes that you remain United Kingdom resident for the whole tax year unless split-year treatment applies, while the French fisc considers that your worldwide income has been taxable in France since the day your family life moved across the Channel. Both letters look official. Both cannot be right about the same income, yet neither is a bluff: each country applies its own residence test first, and only afterwards does the France–United Kingdom double tax treaty of 19 June 2008 decide which residence wins. This guide explains, for a British reader settling in France after Brexit, when you become French tax resident in your arrival year, why HMRC may still treat you as United Kingdom resident for the same year, what to put on your first French tax return, and how to challenge double taxation when both countries send a bill. France, unlike the United Kingdom, has no split-year rule: once your foyer (the place where you normally live and centre your personal life) moves to France, Article 4 A of the French Tax Code taxes you on all of your income from that date. The treaty tie-breaker — permanent home, then centre of vital interests, then habitual stay, then nationality — settles genuine dual-residence cases. Because the pillar guide already covers the tie-breaker in general terms, this article does the practical job for the arrival year itself: the date your residence flips, the forms to file, the evidence that proves it, and the deadlines for pushing back.
I. When Do You Become French Tax Resident in Your Arrival Year?
A. How France decides you live here now: your home, your 183 days and the day-count myth
French domestic law asks one question before anything else: do you have your domicile fiscal (tax home) in France? If the answer is yes, Article 4 A of the Code général des impôts (French Tax Code) provides that “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” (Article 4 A, Tax Code). In plain English: French tax residents pay French income tax on their worldwide income. The stakes of the arrival date are therefore immediate, because every pound of salary, pension, rent or interest received after that date falls inside the French net, while income received before it generally stays outside, save for French-source income which France taxes anyway.
Article 4 B of the same Code then gives three alternative tests, and meeting any single one is enough: “Les personnes qui ont en France leur foyer ou le lieu de leur séjour principal” (Article 4 B, Tax Code), or persons working in France, or “Celles qui ont en France le centre de leurs intérêts économiques” (same Article 4 B). The foyer means the household home, the séjour principal means the place of the main stay, and the centre des intérêts économiques means the centre of economic interests. For a British family arriving with a one-way move, the foyer test usually bites first: the administration’s own guidance on service-public.fr explains on its domicile fiscal page that your tax home is in France when your household habitually lives there, and that the household counts the spouse, civil partner or cohabiting partner plus the children. Where the whole family relocates together, the analysis is short. Where one spouse arrives first while the other winds up affairs in Britain, the household may be treated as moved only when family life genuinely recentres, which is why keeping dated evidence of the move matters from day one.
Single arrivals without children are judged differently. The same official guidance states that a single person without children has their household where they habitually live, disregarding business trips. The courts read this exactly as written. The Administrative Court of Appeal of Paris recalled in a 2023 residence dispute that “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” (CAA Paris, 20 October 2023, No 22PA00816). In that case the taxpayer proved 201 days in Israel against 164 days in France, yet the court held him French resident, noting “164 jours en France à comparer à 201 jours en Israël” but finding a permanent Paris flat with a cleaner all year, post delivered there, matching utility consumption, family property made available near Paris and French bank accounts receiving his pensions. Day-counting alone lost against the bundle of real-life ties. British advisers repeat a comforting “183-day rule” as if presence below that line guaranteed non-residence; French competitor commentators themselves call it a myth, and the case law confirms it: a single criterion met out of three suffices, and the foyer criterion does not count days at all.
The 183-day figure is not imaginary, but it governs only the second test. Service-public.fr puts it this way: your tax home is in France if it is the place of your main stay, meaning at least 183 days in the year, hence more than six months. So a retired couple who keep their only real home in Kent but spend seven months in a Dordogne cottage will be French resident under the main-stay test even though their family foyer arguably stayed British. Conversely, spending fewer than 183 days in France never saves you if your foyer or your economic centre has already moved. For the arrival year this has a sharp consequence: there is no French equivalent of a split-year election. If your foyer moves on 14 June, France treats you as resident from that point within the year of arrival, and the return you file the following spring must reflect it. The exact moving date therefore deserves the same care as an exchange-of-contracts date: removal invoices, ferry or tunnel bookings, the état des lieux (check-in inventory) of the French rental, school enrolment letters and the closure or retention of the United Kingdom home all fix it.
Two further traps catch Britons in the arrival year. First, professional activity: directing a French company, or working full-time in France even while the family supposedly stayed behind, can make you resident under the work test on its own. Second, the economic-centre test: keeping a London salary while living full-time in France does not keep you non-resident, because the salary is taxed where the work is done and the treaty gives France, as the residence state, the right to tax the rest with a credit. Readers who want the general dual-residence framework should read our pillar guide on how the treaty tie-breaker decides Franco-British dual residence; what follows here is the arrival-year machinery that the pillar guide assumes.
B. Why HMRC may still call you United Kingdom resident: the Statutory Residence Test and split-year treatment
HMRC runs a completely separate test, and Brexit changed nothing about it: the Statutory Residence Test applies to Britons exactly as it does to anyone else leaving the United Kingdom. In outline, you are United Kingdom resident for a tax year if you meet an automatic United Kingdom test — broadly, 183 days or more in the United Kingdom, or a single home in the United Kingdom for a long stretch, or full-time work there — and you escape residence only if you meet an automatic overseas test, failing which a sufficient-ties test counts your days against your connections. The detail sits in HMRC’s RDR3 guidance, but the arrival-year point that matters for this article is narrower: unlike France, the United Kingdom year can be cut in two. GOV.UK states the principle plainly on its residence guidance page: the tax year is usually divided into a non-resident part and a resident part, through a mechanism known as split-year treatment.
Split-year treatment is not automatic and it is not available on every departure. The same GOV.UK page warns that split-year treatment is refused where the taxpayer lives abroad for less than a full tax year before returning to the United Kingdom. Beyond that headline condition, the claim depends on fitting one of HMRC’s numbered split-year cases — starting full-time work abroad, a partner’s move, a return to the United Kingdom, and similar fact patterns — each with its own day-count and presence conditions, and each declared on the Self Assessment return with the relevant case number. A British family that moves to France in June and stays will normally secure split-year treatment for the departure year, so that United Kingdom tax on foreign income stops at the point of departure. A consultant who moves in June but flies back to London three days a week, keeping a flat and 100-plus days of United Kingdom presence, may fail the case conditions and remain United Kingdom resident for the entire United Kingdom tax year running 6 April to 5 April — a year that straddles two French calendar years and therefore overlaps the French arrival year twice over.
This overlap is where the double bill is born. Take a concrete pattern: the Duponts leave Leeds on 20 June, rent in Lyon from 1 July, and Mr Dupont keeps a three-day-a-week London contract until Christmas. France sees a foyer in Lyon from July and taxes worldwide income from that date. HMRC sees sufficient ties plus heavy United Kingdom days and taxes the whole 6 April–5 April year, granting split-year treatment only if a case fits. Both positions are legally reasoned under domestic law, and shouting that one must yield to the other achieves nothing: the treaty tie-breaker exists precisely because two domestic claims can coexist. Article 4(1) of the 2008 France–United Kingdom treaty, as published by GOV.UK, first confirms the overlap — anyone liable to tax under either State’s domestic law counts as a resident of that State — and Article 4(2) then breaks it through a cascade starting with the permanent home and continuing, where homes exist in both States, with the State of closer personal and economic relations, the centre of vital interests. The full treaty text is on GOV.UK’s page for the 2008 United Kingdom and France Double Taxation Convention, and the residence position for any year is explained on GOV.UK’s residence guidance. Note the order of the cascade: permanent home first, vital interests second, habitual stay third, nationality fourth. Many Britons argue the case backwards, starting with “but I am British”, when nationality only counts if every earlier test draws.
Practical consequences follow for the months between the move and the first returns. Keep paying United Kingdom tax at source where due and keep filing Self Assessment while the position is unclear; a premature claim of non-residence followed by a failed split-year case produces interest and penalties that dwarf the adviser’s fee. On the French side, register the arrival with the local tax office, open the online personal space, and keep the United Kingdom P45, P60 and P85 alongside the French paperwork, because the treaty relief you will claim in France needs the United Kingdom figures to match. Above all, do not assume the two tax years align: the United Kingdom year ends on 5 April while the French year ends on 31 December, so the same salary can sit in different reporting periods on each side. Reconciling the two calendars line by line is unglamorous work, but it is exactly what the inspector on either side will ask to see.
II. What Do You Declare, Where, and How Do You Challenge a Double Bill?
A. Your first French return after arrival: the forms, the dates and the credit that prevents double tax
The French administration states the arrival-year filing rule without ambiguity. The impots.gouv.fr international desk explains on its arrival page that, in the year after arrival, you declare online or by sending paper form 2042 to the tax office of your new French home, reporting all income received between the return date and 31 December of the arrival year. Three points deserve emphasis because British newcomers routinely get them wrong. First, the return is filed the spring after arrival: arrive in 2026, declare in spring 2027. Second, only income received between the arrival date and 31 December goes on it — not the January salary earned while still living in Leeds. Third, the main form 2042 (déclaration d’ensemble des revenus, the overall income return) travels with its annexes: form 2047 for income received abroad, form 2044 for rental income from property, and form 2042-C for supplementary income such as capital gains, each downloadable from impots.gouv.fr. The arrival date written on the 2042 fixes everything downstream, so it must match the evidence pack, not a convenient round month.
Inside that return, each category of income follows the treaty allocation, and the treaty, not domestic instinct, decides who taxes what. Employment income is taxable where the work is physically done, so London days stay taxable in the United Kingdom with France granting a credit, while Lyon days are French. Pensions, investment income and rents each have their own treaty article, and the return must show the gross foreign amount on form 2047 before claiming the matching credit on form 2042, because the credit is the visible proof that double taxation was relieved rather than ignored. British-source dividends or interest received before the move generally stay outside the French return altogether, since pre-arrival you were not French resident; but French-source income of the pre-arrival period — rent from a French flat you already owned, for example — remains taxable in France under the non-resident rules. Article 164 A of the Tax Code provides that “Les revenus de source française des personnes qui n’ont pas leur domicile fiscal en France sont déterminés selon les règles applicables aux revenus de même nature perçus par les personnes qui ont leur domicile fiscal en France.” with the well-known sting that most personal deductions are unavailable. Where the minimum-rate machinery of Article 197 A applies to that pre-arrival French-source slice, the Code warns that “l’impôt ne peut, en ce cas, être inférieur à un montant calculé en appliquant un taux de 20 % à la fraction du revenu net imposable inférieure ou égale à la limite supérieure de la deuxième tranche du barème de l’impôt sur le revenu et un taux de 30 % à la fraction supérieure à cette limite”, subject to the taxpayer proving that the average rate on worldwide income would be lower. The Constitutional dimension of that minimum rate was tested as recently as 2023, when the Conseil d’Etat declined to transmit a priority question of constitutionality on Article 197 A, holding: “Il n’y a pas lieu de renvoyer au Conseil constitutionnel la question prioritaire de constitutionnalité soulevée par M. A….” (CE, 3 February 2023, No 468904). The lesson for newcomers is practical rather than theoretical: the pre-move and post-move slices of the same calendar year can be taxed under different regimes, and netting them together on one line invites a reassessment.
Two further filing points complete the picture. Bank accounts held in the United Kingdom must be declared each year on the foreign-account form, and the arrival year is the moment to start; omission extends the administration’s recovery window dramatically. And where the treaty tie-breaker makes you exclusively United Kingdom resident for the arrival year despite a French home — the departure-year mirror image — the French return should still be filed to record the position and claim treaty protection, rather than filed late with a penalty after the inspector writes first. The governing domestic hooks stay the same throughout: worldwide taxation once resident under Article 4 A of the Tax Code, the three residence tests under Article 4 B of the Tax Code, French-source taxation of non-residents under Article 164 A, the minimum rate under Article 197 A, and the official filing method on impots.gouv.fr’s arrival page with the residence criteria summarised on service-public.fr’s domicile fiscal page.
For completeness, the foreign investment income declared on form 2047 is defined broadly: Article 120 of the Tax Code covers, among others, “Les intérêts, arrérages, et tous autres produits de rentes, obligations et autres effets publics des gouvernements étrangers”, so United Kingdom gilts and bonds held on arrival fall squarely inside the French declaration net from the residence date.
B. Deadlines, the proof pack and the routes for challenging a double charge
When both bills arrive, procedure beats indignation. Start with time limits, because they run from different dates on each side. In France the administration’s general right to reassess income tax runs to the end of the third year following the year of liability: the Procedures Book states “Pour l’impôt sur le revenu et l’impôt sur les sociétés, le droit de reprise de l’administration des impôts s’exerce jusqu’à la fin de la troisième année qui suit celle au titre de laquelle l’imposition est due.” (Article L169 of the Livre des procédures fiscales), extended to ten years for hidden activity or undeclared foreign accounts, which is another reason to declare the United Kingdom accounts from year one. Your own challenge window is shorter: the claim for relief (réclamation contentieuse, the formal complaint to the tax office) must generally reach the fisc by 31 December of the second year after the disputed assessment, so a wrong 2026 assessment challenged in 2027 must be contested by the end of 2028. In the United Kingdom, the Self Assessment amendment and overpayment-relief clocks run on their own rules from the end of the relevant United Kingdom tax year, and HMRC’s split-year case must have been claimed correctly on the return in the first place. Diary both calendars the week you move; diarying only one is how deadlines are missed.
Next, build the proof pack before the dispute, not after. The CAA Paris decision quoted above is a checklist written in reverse: the taxpayer lost because the administration produced a permanent flat, a year-round cleaner, delivered post, matching utilities, nearby family property and French bank accounts, against which bare day-counts weighed nothing. Your pack should therefore prove the positive on the winning side of the tie-breaker. For a French-residence claim: the lease or purchase deed with its start date, the removal firm’s inventory, travel bookings showing the one-way pattern, French utility contracts and consumption, children’s school certificates, French health registration, closure or letting of the United Kingdom home, and bank statements showing daily spending moving to France. For a United Kingdom-residence defence of the pre-move period: the mirror image, plus the P85 departure form, employer letters fixing the place of work, and boarding passes. Keep everything for at least the French recovery period plus a margin, and keep it in both languages where the original is English, because the French inspector works from French documents.
Then challenge in the right order. First, correct the return: an error caught early is fixed by an amended return or an online correction, which costs nothing and concedes nothing. Second, file the formal réclamation with the French tax office that issued the assessment, setting out the arrival date, the applicable treaty article for each income category, and the credit computation, with the evidence attached and a copy kept with proof of posting. Third, if the office rejects or ignores the claim, appeal to the administrative court within two months of the rejection. Fourth, for genuine dual-residence conflicts that survive domestic remedies, request the mutual agreement procedure: the treaty provides that where nationality and earlier tests cannot settle residence, the competent authorities decide together, and the parallel transfer-pricing-style negotiation between HMRC and the French direction des impôts can eliminate double taxation that neither office could concede alone. Throughout, pay what is formally due where payment suspends enforced recovery only if the proper stay is requested; unpaid disputed tax accrues late-payment interest on both sides of the Channel, and a won principle can still cost a lost surcharge.
Three frequent errors deserve a final warning. The first is treating the 183-day count as a shield: as shown, the foyer test needs no day-count at all, and the Paris court taxed a taxpayer with fewer French than foreign days. The second is assuming nationality decides: under the treaty cascade it is consulted almost last. The third is filing only on one side: a French resident who ignores Self Assessment while HMRC still counts ties, or a departing Briton who ignores the French 2042 while keeping a French flat, manufactures the very double bill this article teaches you to dismantle. File everywhere a filing is arguably due, claim the treaty explicitly on each return, and keep the two filings numerically consistent.
Conclusion
Your arrival year is the one year when both countries can plausibly tax you, and the system for resolving it is orderly if you work it in sequence: fix the exact moving date, apply the French foyer, stay and economic-centre tests without day-count illusions, check HMRC’s split-year case on its own terms, declare worldwide income in France only from arrival while filing the treaty credit for United Kingdom-taxed items, and challenge any double charge through correction, formal complaint, court appeal and mutual agreement within the time limits. The treaty tie-breaker rewards the taxpayer whose real life visibly sits in one country — permanent home, vital interests, habitual stay, then nationality — and punishes the taxpayer who argues from passports and calendars while the post, the cleaner, the school run and the bank statements all point across the Channel. Move the facts first, file them consistently on both sides, and the law will follow the life you actually moved.