You did everything by the book. Years of work in Britain, a private pension built up with a UK provider, and at retirement you took the famous 25% tax-free lump sum — the Pension Commencement Lump Sum, or PCLS — before settling in the Dordogne, Brittany or Provence. The money was tax-free in Britain. Then the French avis d’impôt (the annual tax bill sent by the French tax office) arrives, and the same lump sum is sitting in your taxable income. In some cases HMRC has also operated UK tax on part of the payment, because the provider applied PAYE as a precaution. One lump sum, two countries taxing it, and a bill that can run into tens of thousands of euros. This guide explains, for a British resident of France after Brexit, where your UK pension lump sum is really taxed, how France calculates the charge, which forms get the British tax refunded, and how to challenge a wrong bill in time. Every French term is explained as we go, and every decisive statement is anchored to the exact official text.
I. Your UK pension lump sum has arrived in France: which country is allowed to tax it after Brexit?
A. My 25% tax-free lump sum is taxed in France: can the treaty stop the double tax?
The starting point is a shock most British retirees discover too late: what is tax-free in Britain is not automatically tax-free in France. On the British side, the government states the rule plainly: you can usually take “up to 25% tax-free” from your pension savings, within a maximum tax-free amount of £268,275 known as the lump sum allowance. France does not copy that exemption. Under French domestic law, Article 79 of the General Tax Code provides: “Les traitements, indemnités, émoluments, salaires, pensions et rentes viagères concourent à la formation du revenu global servant de base à l’impôt sur le revenu. Il en est de même des prestations de retraite servies sous forme de capital.” In plain English: pensions and retirement benefits paid as a lump sum (prestations de retraite servies sous forme de capital) join your overall taxable income for French income tax. Your PCLS therefore enters the French tax base even though HMRC treated it as tax-free.
The rescue comes from the double tax treaty, the bilateral agreement that divides taxing rights between the two countries so the same income is not fully taxed twice. The current agreement is the convention signed on 19 June 2008, published in France in early 2010, and it is fully in force after Brexit: the end of EU membership did not cancel bilateral tax treaties. Its Article 18 reserves private pensions to the country where the pensioner lives, covering pensions paid for past employment (“au titre d’un emploi antérieur”), so that only the state of residence may tax them. If you are fiscally resident in France (résident fiscal de France, meaning France is the country where you are liable to tax on your worldwide income), your UK private pension and the lump sum attached to it are taxable only in France. The United Kingdom must then give up its tax: either it exempts the payment at source once your French residence is proven, or it refunds tax wrongly deducted. The French tax administration confirms this architecture in its official commentary on the British convention, which organises the relief procedure for French residents receiving British pensions.
French courts apply this residence-only logic strictly, and they insist on two separate checks: are you genuinely resident, and does the payment fall under the pensions article? The Lyon administrative court of appeal gave a useful illustration of the method in a case about a foreign lump sum, holding that European coordination law “n’opère pas de distinction entre les pensions versées sous forme de rente mensuelle et celles versées sous forme de capital” — it makes no distinction between pensions paid as a monthly annuity and those paid as a lump sum (CAA Lyon, 2nd chamber, 16 March 2023, No. 21LY03252, full decision on Légifrance). The form of payment does not change the treaty analysis: a capital sum that represents pension rights is still pension income for treaty purposes. The Toulouse court spelled out the twin test even more clearly under a treaty worded identically to the Franco-British one: “Sous réserve des dispositions du paragraphe 2 de l’article 19, les pensions, rentes viagères et autres rémunérations similaires payées à un résident d’un Etat contractant ne sont imposables que dans cet Etat” (CAA Toulouse, 1st chamber, 13 October 2022, No. 20TL22832, full decision on Légifrance). In that case the judges verified residence first — the couple had to show they were genuinely liable to tax in the other country — and only then applied the pensions article to exempt the income in France. The lesson for a British reader is direct: keep your proof of French tax residence ready (French tax notices, attestation de résidence from your local tax office, rental contract or utility bills), because the treaty protects residents, not merely people who happen to own a house in France.
In practice, then, the answer to the headline question is reassuring but conditional. Yes, the treaty stops the double tax on your private pension lump sum: France taxes, Britain stands down. But three conditions must hold together. First, you must be fiscally resident in France for the year of payment. Second, the lump sum must come from private employment — a personal pension, an employer’s occupational scheme, a SIPP (Self-Invested Personal Pension, a UK DIY pension wrapper) — and not from government service, which follows the opposite rule examined below. Third, you must actively claim the British relief: HMRC does not always know you live in France, and a UK provider that has your old British address on file may operate emergency tax by default. The French tax office (service des impôts des particuliers, your local personal tax centre) can certify your residence on the treaty claim form, and the British tax is then refunded or stopped at source, as explained in Part II. If any of the three conditions fails — for example you took the lump sum while still UK-resident and moved to France the same year — the split-year analysis becomes delicate, and you should get advice before filing either return.
B. The government-service exception that reverses everything: nurses, teachers, soldiers and civil servants
Everything above collapses if your pension rewards service to the British state itself. Article 19 of the same treaty, on public functions (fonctions publiques), keeps government pensions taxable in the paying country: pensions for work performed for a contracting state “ne sont imposables que dans cet Etat” (they are taxable only in that state), with one narrow escape — they become taxable only in the other country if the pensioner lives there and holds its nationality (“en possède la nationalité”) without also holding the first country’s nationality. Take a concrete case: a retired NHS nurse, a former local-authority teacher, a police officer or a member of the armed forces, now living in France as a French resident but holding only British nationality. The pension is paid by the British state for service to that state, so it remains taxable only in the United Kingdom. France must exempt it — though it may take the amount into account to set the rate on your other income, a mechanism called taux effectif (the exempt income pushes the rest of your income into a higher bracket without being taxed itself).
The mirror image matters just as much. If you are a French national living in France drawing a French civil-service pension, France keeps the taxing right. And the escape hatch is genuinely narrow: only a person who lives in France, holds French nationality and does not hold British nationality at the same time sees the British government pension become taxable only in France. Dual nationals are caught by the exclusion — holding both nationalities at once removes the escape — so a Franco-British dual citizen in France with a UK civil-service pension stays taxable in the United Kingdom. Before Brexit these questions rarely reached the courts for Britons; since 2021 they arrive weekly, because former public-sector workers who moved to France for retirement assumed all UK pensions were treated alike. They are not. Misclassifying a government pension as a private one on your French return produces two symmetrical errors: you pay French tax you do not owe, and you fail to settle the British tax you do owe, with interest building on the UK side.
How do you tell which side your scheme falls on? Ask who paid you for the underlying work. A pension from the NHS Pension Scheme, the Teachers’ Pension Scheme, the Principal Civil Service Pension Scheme, the Armed Forces Pension Scheme or a local-authority scheme such as the LGPS (Local Government Pension Scheme) is normally government service, even if it is administered by an outside manager. A pension from a private employer, a personal stakeholder pension or a SIPP funded from private-sector earnings is normally private employment under Article 18. Funded versus unfunded does not decide the issue; the identity of the former employer does. The Bordeaux court confirmed how strictly judges police the boundary: a French-resident taxpayer who argued his Norwegian state pension should escape French tax lost in full, because he could not bring himself within the government-service wording, and the court dismissed the claim entirely (CAA Bordeaux, 5th chamber, 2022, No. 21BX02149, full decision on Légifrance). The same rigour applies in reverse to Britons in France. When in doubt, write to the scheme administrator and ask for written confirmation of the employer’s status, keep the letter with your tax file, and tick the correct box on the return rather than hoping the two tax offices will sort it out between themselves. They will not.
II. How France calculates the charge, and how you pay less or challenge the bill
A. How France taxes the lump sum: the scale, the spreading mechanism and the 7.5% option
Once France is confirmed as the taxing country, the next question is how much. The default rule is unforgiving: the lump sum is added to your other income and taxed at the progressive scale (barème progressif), the graduated rates that rise with total household income. The official tax doctrine states the principle without ambiguity: lump-sum retirement benefits fall within the pension rules and are taxable under the ordinary pension regime (“règles de droit commun des pensions”), by reference to the pensions paragraph of Article 158 of the General Tax Code (BOI-RSA-PENS-30-10-20, official tax commentary). Two features soften the blow. First, pensions carry a standard 10% allowance (abattement de 10%): the Code provides that “Les pensions et retraites font l’objet d’un abattement de 10 % qui ne peut excéder 4 439 €.” Each retired member of the household (foyer fiscal, the family unit taxed together) gets the allowance within that ceiling, which is revised each year. Second, a lump sum counts as legally exceptional income (“revenus exceptionnels”), so it qualifies for the quotient mechanism (système du quotient) defined in Article 163-0 A of the Code, which spreads the spike to avoid one year’s income being crushed by the top rate — and it does so whatever the amount. In practice the tax office divides the lump sum to compute the extra tax as if the income had arrived in slices, then multiplies back — a calculation your return software performs if you tick the exceptional-income box, but one you must check, because an unticked box can double the bill.
Alongside the scale-plus-quotient route sits a flat-rate alternative many advisers miss: taxation at 7.5% (prélèvement forfaitaire de 7,5%), available for lump sums on the beneficiary’s express and irrevocable election (“sur demande expresse et irrévocable du bénéficiaire”), under Article 163 bis-II of the General Tax Code (same official commentary). The words expresse et irrévocable matter: you must expressly elect the flat rate, and you cannot change your mind afterwards, so the choice has to be modelled before filing. The gateway condition concerns the contributions that built the rights: for foreign-source pensions, the contributions must have enjoyed some tax advantage (“un avantage fiscal”) in the country concerned — deduction, exemption, credit or similar — for the employee or the employer (same commentary). For a British private pension this test is usually met, because UK registered pension schemes give tax relief on contributions — but you must be able to prove it with career statements, payslips, tax notices and residence certificates if the administration asks (“sur demande de l’administration”). Keep P60s, scheme booklets showing UK tax relief, and employer letters in a dedicated file; the tax office asks for them years later, when providers have archived old records.
Where contributions were never deductible anywhere, a third route opens under Article 120-6°-bis of the General Tax Code: “Les produits attachés aux prestations de retraite versées sous forme de capital et perçues en exécution d’un contrat souscrit auprès d’une entreprise établie hors de France, lorsque le bénéficiaire justifie que les sommes versées durant la phase de constitution des droits, y compris le cas échéant par l’employeur, n’étaient pas déductibles du revenu imposable et n’étaient pas afférentes à un revenu exonéré dans l’Etat auquel était attribué le droit d’imposer celui-ci”. Those gains are treated as investment income rather than pension income, which changes both the rate and the social charges. Do not elect the 7.5% option lightly in that situation, because the Lyon case shows the administration challenges elections aggressively: Mrs A. had taken a Swiss capital pension of about 1.5 million euros, the tax office rejected her flat-rate election and reassessed her, and the court had to untangle income tax, the 10% surcharge and social charges line by line (CAA Lyon No. 21LY03252). The same judgment delivered a second gift to lump-sum recipients: the court capped the French social charges on the foreign capital pension at the level of French-source pensions actually paid that year, ordering that “Le montant des contributions sociales dues à raison de la pension de retraite de réversion en capital versée en 2015 à Mme A… est ramené à 3 094 euros.” If you hold an S1 healthcare certificate (certificat S1, the form by which the UK pays for your French healthcare) or otherwise belong to another state’s health system, you may owe no French social charges at all on the lump sum — but that exemption is never automatic and must be claimed with the S1 attached.
B. Declare it, get the British tax back, and challenge a wrong bill before the deadline
Declaration comes first, because everything else — the treaty relief, the quotient, the 7.5% election, the social-charge exemption — depends on boxes correctly ticked. French law makes the obligation personal and annual: Article 170 of the General Tax Code states “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”. Concretely, a British resident declares the lump sum on the foreign-income form No. 2047 (formulaire 2047 des revenus encaissés à l’étranger) and carries the total to the main return No. 2042, ticking the exceptional-income section for the quotient and attaching the express 7.5% election where chosen. Report the gross amount in euros at the payment-date exchange rate used by the administration, keep the provider’s P45 or payslip showing any UK tax deducted, and never net off the British tax before declaring: France taxes the gross sum and relieves the foreign tax separately. If the provider deducted UK tax at source, the treaty refund runs through the official channel described in the British-convention commentary: the claimant files a request on the “formulaire France-Particulier” (the France-Individual form) for individuals (treaty application commentary). Your French tax office certifies residence on the form, you send it to HMRC, and the British tax is repaid or switched off at source. Start that process the month the lump sum lands, not the following spring: HMRC backlogs are long, and the French bill will arrive first.
If the French bill is wrong — lump sum taxed without quotient, 7.5% election ignored, government pension taxed in France contrary to Article 19, British tax not credited, or social charges levied despite your S1 — challenge it through the réclamation (the formal complaint to the tax office), and do it fast. The tax administration’s own guidance invites you to start by filing your complaint online (“formuler une réclamation directement en ligne”) from your personal tax account (impots.gouv.fr, contesting your tax). Two warnings from the same page decide cases: filing does not pause collection, so expressly ask to “demander un sursis de paiement” (a stay of payment while the complaint is examined) — and note the reply target of six months (“délai de 6 mois”) from filing. Diary that six-month date: silence for six months is an implied rejection you can take to the administrative court (tribunal administratif). Attach everything the cases above show judges want: the treaty articles, the provider’s statements, proof of contributions’ UK tax relief, the S1 if you claim the social-charge exemption, the France-Individual form and HMRC’s reply, and a one-page computation showing the correct quotient or 7.5% result. For readers in Paris and the Île-de-France, file online first, then direct court appeals to the tribunal covering your address — Paris for the capital, Montreuil, Cergy-Pontoise, Melun or Versailles for the inner and outer suburbs — and keep the paper trail Paris judges expect: every letter sent en recommandé avec accusé de réception (registered post with return receipt).
Conclusion
Your British tax-free lump sum does not stay tax-free when you live in France, but it must not be taxed twice. The treaty gives France the taxing right over private pension lump sums and obliges Britain to refund or forgo its tax; government-service pensions follow the mirror rule and stay British. Inside the French bill, three calculations compete — the progressive scale softened by the 10% allowance and the quotient, the irrevocable 7.5% flat rate for deductible-contribution schemes, and the investment-income route where nothing was ever deducted — and the right choice can move the bill by five figures. Social charges deserve a separate challenge, with the S1 certificate and the courts’ capping case law as your leverage. Declare gross on forms 2047 and 2042, launch the France-Individual refund at once, and attack errors by online réclamation with a stay of payment inside the deadline. Taken in that order, the lump sum that looked like a double-tax trap becomes what it was meant to be: the capital foundation of your French life.
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