You did everything in the right order. You moved to France after Brexit, you drew your United Kingdom State pension, you obtained an S1 healthcare certificate (the portable document by which the United Kingdom confirms that it pays for your medical care in France), you registered that S1 with your local health fund, the CPAM (caisse primaire d’assurance maladie), and you file a French tax return every year. Then you look closely at what is taken from your pension and you discover a second layer beneath income tax: France’s social charges, the prélèvements sociaux, which can reach 9.1 per cent of the gross amount of your pension. Your reaction is entirely natural. Your healthcare is paid for by Britain, not by France, so why should your pension fund the French health system as well? The answer, for many British pensioners, is that it should not. Where your S1 covered the year concerned, the CSG and CRDS taken from your pension are normally recoverable, and the exemption can be organised for the future. This guide explains the French calculation line by line, the single piece of European reasoning that cancels it, the exact proof the administration demands, and the strict deadline that defeats late files.

I. Why France takes CSG and CRDS from your UK pension and what the 8.3%, 6.6% and 3.8% rates cost you

A. Your UK pension is inside the French charge: who pays CSG and CRDS on replacement income and at what rate

French social charges are taxes, not contributions, even though the money partly finances social protection. That classification is the starting point of everything that follows. Pensions are what French law calls replacement income (revenus de remplacement), and the official public-service guide states the position without ambiguity: “Retirement pensions are subject to the CSG and CRDS.” The CSG is the generalised social contribution (contribution sociale généralisée); the CRDS is the contribution for the repayment of the social debt (contribution pour le remboursement de la dette sociale). Both are deducted at source from French pensions, and both are assessed on foreign pensions, including a United Kingdom State pension or private pension, once you are fiscally domiciled (domicilié fiscal) in France. Readers who are unsure about the residence test itself will find it examined in detail in our guide on when a British national becomes French tax resident and what happens when both tax offices claim you.

Liability for the CSG on replacement income is defined by Article L.136-1 of the Social Security Code (Code de la sécurité sociale), which catches “Les personnes physiques qui sont à la fois considérées comme domiciliées en France pour l’établissement de l’impôt sur le revenu et à la charge, à quelque titre que ce soit, d’un régime obligatoire français d’assurance maladie” — natural persons who are at once treated as domiciled in France for income tax purposes and covered, in any capacity whatever, by a compulsory French health insurance scheme. The two conditions are cumulative, and the second is where most British pensioner files are won or lost. A retiree who relies on French universal cover, the PUMa (protection universelle maladie), is covered by a compulsory French scheme and therefore meets the condition. A retiree whose healthcare is paid for by the United Kingdom under a registered S1 is not covered by the French scheme for that purpose, and the condition fails. Everything practical in this article flows from that single distinction, so establish now, for each year in dispute, which scheme actually carried your health cover.

The CRDS follows the same persons. Article 14 of Ordinance No 96-50 of 24 January 1996 on the repayment of the social debt (ordonnance n° 96-50 du 24 janvier 1996 relative au remboursement de la dette sociale) provides that “Il est institué une contribution assise sur les revenus d’activité et de remplacement mentionnés à la section 1 du chapitre 4 du titre 3 du livre 1 du code de la sécurité sociale perçus par les personnes physiques désignées à ce même article.” — a contribution is created on the employment and replacement income referred to in that section of the Social Security Code, received by the natural persons designated in that same article — and adds that “Cette contribution est soumise aux conditions prévues aux articles L. 136-1-1 à L. 136-4 du même code.” In plain terms, whoever escapes the CSG on pensions escapes the CRDS too, and whoever is liable for one is liable for the other. There is no separate CRDS-only argument to construct and no separate CRDS-only defence for the administration to raise.

The headline rate on pensions is 8.3 per cent CSG. Article L.136-8 of the Social Security Code provides that “Sont assujetties à la contribution au taux de 8,3 % les pensions de retraite, et les pensions d’invalidité.” — retirement pensions and invalidity pensions are subject to the contribution at the rate of 8.3 per cent. But most pensioners do not pay that headline rate. Depending on household income, three lower outcomes exist: total exemption (the zero rate), a reduced rate of 3.8 per cent, and a median rate of 6.6 per cent. The public-service guide confirms that “It exists 4 CSG rate on retirement pensions,” namely the zero rate, the reduced 3.8 per cent, the median 6.6 per cent and the normal 8.3 per cent. The same page adds a warning that surprises many readers: “The levies are applied on the entire pension.” There is no slice taxed at one rate and another slice at a different rate; a single rate, determined by your reference income, applies to the whole pension.

B. What the bill looks like in pounds and pence: income thresholds, the 0.5% CRDS, the 0.3% Casa and the deductible slice

The rate you pay is set by your reference tax income (revenu fiscal de référence, universally shortened to RFR), which is the figure shown on your French tax notice, the avis d’imposition. For charges levied in 2026, the administration looks at the income declared in 2025 for the year 2024. For a household with one tax share (une part de quotient familial), the 2026 scale runs as follows: up to 13,048 euros of RFR, total exemption; from 13,049 to 17,057 euros, the reduced 3.8 per cent rate; from 17,058 to 26,472 euros, the median 6.6 per cent rate; above 26,472 euros, the normal 8.3 per cent rate. The thresholds rise with each additional half-share, and the detailed table is published on the official public-service page cited above. One protection is built into the movement between rates: moving up from the reduced 3.8 per cent rate to the median 6.6 per cent, or straight to the normal 8.3 per cent, normally requires your income to have exceeded the reduced-rate ceiling for two consecutive years, so a single exceptional year does not permanently reclassify you.

On top of the CSG comes the CRDS at a flat 0.5 per cent, except for pensioners at the zero rate, who are exempt from CRDS as well, and a further solidarity levy, the additional autonomy contribution (contribution additionnelle de solidarité pour l’autonomie, known as Casa), at 0.3 per cent for pensioners at the median and normal rates. Pensioners at the reduced 3.8 per cent rate are exempt from Casa. The combined burden is therefore 9.1 per cent at the normal rate (8.3 CSG plus 0.5 CRDS plus 0.3 Casa), 7.4 per cent at the median rate, 4.3 per cent at the reduced rate, and nothing at the zero rate. On a United Kingdom pension of 24,000 euros a year, the difference between the normal rate and exemption is 2,184 euros every year — and the difference accumulates, because each wrongly charged year must be reclaimed separately before its own deadline.

One partial consolation exists for pensioners who genuinely owe the charge: part of the CSG is deductible from taxable income. The deductible slice is 5.9 per cent at the normal rate, 4.2 per cent at the median rate, and the whole 3.8 per cent at the reduced rate. The remainder stays inside taxable income. Deductibility softens the bill but never erases it, and it is irrelevant to the readers this article is written for — pensioners whose S1 means no charge was ever due. Do not let the administration, or your own bank manager, deflect an exemption file into a deductibility discussion. The question is not how much of an unlawful charge is deductible. The question is whether the charge was lawful at all.

Before turning to the exemption, note the boundary of this article. It deals only with pensions — State pension, occupational pension, personal pension, widow’s pension — which are replacement income under Article L.136-1. Rental income from a French flat, interest from savings and capital gains on shares are asset income (revenus du patrimoine) governed by a different article, Article L.136-6, with its own exemption paragraph, and are examined in our guide on how British residents declare United Kingdom savings and investment income in France. The reasoning below extends to that income by a parallel route, but the paperwork, the rates and the traps differ. Keep the two files physically separate: one claim for the pension charges, one claim for the asset-income charges, each with its own proof and its own deadline.

II. How your S1 cancels the charge and how to recover what France wrongly took

A. One State, one scheme: the single-legislation rule that exempts S1 pensioners, and the paper that proves it

European social security coordination rests on one simple rule: a person is subject to the legislation of a single State at a time. The French Court of Cassation (Cour de cassation) restated it in plain terms in September 2025, holding that the coordination regulations “consacrent le principe d’unicité de la législation de sécurité sociale, selon lequel la personne à laquelle les règlements s’appliquent n’est soumise qu’à la législation d’un seul État membre, en sorte que celle-ci, affiliée à un régime de sécurité sociale d’un État membre, ne doit pas contribuer au régime de sécurité sociale d’un autre État membre” — they enshrine the principle of a single applicable social security legislation, under which a person covered by the regulations is subject to the legislation of one Member State only, so that a person affiliated to the social security scheme of one Member State must not contribute to the scheme of another. The Court anchored that statement expressly in the European Court of Justice’s 2015 de Ruyter ruling (“CJUE, arrêt du 26 février 2015, De Ruyter, C-623-13, point 35”): Court of Cassation, Second Civil Chamber, 25 September 2025, No 22-24.634. Because the CSG and CRDS on pensions finance French health cover, loading them onto a pensioner whose health cover is paid for by the United Kingdom means making that pensioner contribute to two schemes at once — exactly what the single-legislation rule forbids.

The S1 is the document that places you on the British side of that line. The United Kingdom government’s official guidance confirms that “You may be entitled to state healthcare paid for by the UK if you’re a resident in France and receive a UK State Pension or an exportable benefit.” It adds the step that makes the right effective in France: “Once you have an S1 form, you must register it at your local CPAM office.” Registration is not a formality. It is the moment your health cover visibly moves: the CPAM records you as a patient whose care is billed to the United Kingdom, issues your attestation de droits (certificate of entitlement), and in due course your carte Vitale (the green French health insurance card). An S1 left in a drawer, never registered, proves little for the years before registration. A registered S1, matched to the year on the tax notice, is the core of every winning file. If you receive a United Kingdom State pension, apply for the S1 through the NHS Overseas Healthcare Services; dependants of a State pensioner are covered too, but note that a dependant’s cover ends when the dependant starts drawing a personal United Kingdom State pension, at which point a fresh S1 in the dependant’s own name must be obtained and registered.

For asset income, Parliament wrote the same result directly into the statute. Article L.136-6, paragraph I ter, of the Social Security Code provides that “Par dérogation aux I et I bis, ne sont pas redevables de la contribution les personnes qui, par application des dispositions du règlement (CE) n° 883/2004 du Parlement européen et du Conseil du 29 avril 2004 sur la coordination des systèmes de sécurité sociale, relèvent en matière d’assurance maladie d’une législation soumise à ces dispositions et qui ne sont pas à la charge d’un régime obligatoire de sécurité sociale français.” — by way of derogation, persons who, under Regulation (EC) No 883/2004 on the coordination of social security systems, are covered for sickness insurance by legislation subject to those provisions and who are not covered by a compulsory French scheme are not liable to the contribution. For pensions the route is shorter, through the affiliation condition of Article L.136-1 quoted above, but the destination is identical: a pensioner covered by the British scheme under coordination rules is not covered by a compulsory French scheme and therefore sits outside the charge.

Two cautions keep this guide honest. First, the exemption protects only years genuinely covered by coordination. The Conseil d’État confirmed in 2018, endorsing the European Court’s Jahin ruling of 18 January 2018 (Case C-45/17), that a French national residing in a third State outside the European Economic Area and Switzerland, and affiliated there, may lawfully be subjected to French capital levies while a person covered by another Member State’s scheme is exempt under the single-legislation rule: “les articles 63 et 65 du traité sur le fonctionnement de l’Union européenne doivent être interprétés en ce sens qu’ils ne s’opposent pas à la législation d’un Etat membre, telle que la législation française, en vertu de laquelle un ressortissant de cet Etat membre, qui réside dans un Etat tiers autre qu’un Etat membre de l’Espace économique européen ou la Suisse, et qui y est affilié à un régime de sécurité sociale, est soumis, dans cet Etat membre, à des prélèvements sur les revenus du capital au titre d’une cotisation au régime de sécurité sociale instauré par celui-ci, alors qu’un ressortissant de l’Union relevant d’un régime de sécurité sociale d’un autre Etat membre en est exonéré en raison du principe de l’unicité de la législation applicable en matière de sécurité sociale en vertu de l’article 11 du règlement (CE) n° 883/2004” — Conseil d’État, 8th and 3rd Chambers sitting together, 5 March 2018, No 397881. Since Brexit the United Kingdom is a third State, so a Briton who cannot show coordination cover for a given year — no S1, no posted-worker certificate, no applicable agreement — falls on the wrong side of that line for that year. The S1 is what keeps you on the right side. Second, private health insurance, however expensive and however British the insurer, is not affiliation to a social security scheme. Paying Bupa or AXA premiums while also sitting inside the French PUMa scheme leaves the Article L.136-1 condition fully met and the charges fully due. The exemption rewards coordination paperwork, never private cover.

B. Getting the money back: the claim, the 31 December deadline, the proof bundle and the three defences to expect

Social charges on pensions are recovered through the income-tax machinery, so they are challenged through the tax-claim machinery. Article L.190 of the Tax Procedure Book (Livre des procédures fiscales) provides that “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.” — claims concerning taxes and charges of every kind fall within contentious jurisdiction where they seek either the correction of errors in the basis or calculation of the assessment or the benefit of a right arising from a legislative or regulatory provision. An S1-based refund claim is squarely in the second category: you ask for the benefit of the single-legislation right described above. File the claim with the tax office shown on your avis d’imposition, by registered letter with acknowledgement of receipt or through your personal account on impots.gouv.fr, and frame it as a named claim (réclamation contentieuse) identifying each assessment, each year and each amount.

The deadline is strict and it runs separately for every year. Article R*196-1 of the same Book provides 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 ; b) Du versement de l’impôt contesté lorsque cet impôt n’a pas donné lieu à l’établissement d’un rôle ou à la notification d’un avis de mise en recouvrement” — to be admissible, claims must reach the administration no later than 31 December of the second year following, as the case may be, the collection of the assessment roll or notification of a recovery notice, or the payment of the disputed tax where no roll was issued. In practice, charges shown on the autumn 2024 tax notice must be claimed by 31 December 2026; charges on the autumn 2025 notice by 31 December 2027. A claim filed on 2 January is late, however strong the merits, and lateness for one year never contaminates the neighbouring years — but it permanently kills the late one. Diary every assessment the day it arrives, and file year by year rather than waiting to bundle several years together.

Build one proof bundle per year, and keep the originals. The bundle that wins contains five items: a copy of the S1 valid for that year; the CPAM registration certificate (attestation de droits) showing registration covering that year; the pension statements (relevés de pension) from the United Kingdom payer for that year, with amounts and dates; the French tax notice (avis d’imposition) showing the CSG, CRDS and Casa lines disputed; and a one-page computation of the refund claimed, separating CSG, CRDS and Casa. Where the pension is paid gross from Britain and the charges appear only on the French notice, say so explicitly and show both documents side by side. Where a French pension body deducted the charges at source, attach its annual statement too. If any year in the sequence lacks an S1 — typically the gap between arrival in France and the first S1 registration, when many newcomers sit temporarily in PUMa — concede that year openly and claim only the covered years. Conceding the weak year costs nothing and buys credibility for the strong ones; claiming the weak year alongside the strong ones invites a global rejection that must then be unpicked on appeal.

Expect three defences, and prepare the answers now. First, the office will argue that you were covered by a compulsory French scheme for the disputed year, usually because CPAM records show PUMa cover before the S1 registration date or overlapping it. Answer with dates: produce the S1 start date, the CPAM registration date and, where relevant, the letter closing the PUMa cover, and claim only from the date coordination cover began. Second, the office will argue that your S1 was not registered, or not registered in time. An unregistered S1 is the single most common cause of failure. If registration was delayed, say when it actually happened, claim from that date, and register immediately for the current year so the file stops growing. Third, the office may invoke the third-State objection derived from the 2018 case law above, treating post-Brexit Britain as outside coordination altogether. The answer is that the objection concerns persons with no coordination cover; a registered S1 holder is by definition a person whose sickness cover is coordinated, and the Court of Cassation’s 2025 restatement of the single-legislation rule applies to such persons without any Brexit exception. If the office rejects the claim expressly, or stays silent for six months — silence counts as an implied rejection — the dispute moves to the administrative court (tribunal administratif), where the same bundle, organised year by year around the same five documents, is exactly what the judge will want to see. Readers facing a parallel dispute over rental income or savings interest should keep the pension file distinct, as explained in Part I, and readers whose first French tax return is still ahead of them should read our guide on the first French tax return, forms 2042 and 2047 and the missing tax number before the first wrong assessment is ever issued.

Conclusion

A British pensioner living in France is inside the French CSG and CRDS charge in principle: pensions are replacement income, the headline rate is 8.3 per cent with 6.6 and 3.8 per cent bands beneath it, plus 0.5 per cent CRDS and 0.3 per cent Casa, all applied to the whole pension by reference to the household’s reference tax income. But liability under Article L.136-1 demands cover by a compulsory French health scheme, and a pensioner whose healthcare is paid for by the United Kingdom under a registered S1 is not so covered. The Court of Cassation’s 2025 restatement of the single-legislation rule, rooted in the de Ruyter case, is the legal reason; the registered S1 with its CPAM certificate is the practical proof. Years without coordination cover, years of PUMa affiliation and private insurance without an S1 remain chargeable, and the Conseil d’État’s 2018 third-State decision shows the door stays shut for files with no coordination paper at all. For covered years that were wrongly charged, the path is a documented contentious claim, one per assessment, before 31 December of the second following year, after which the administrative court decides on the same bundle. Check the S1 dates, assemble the five documents, diary the deadlines — and stop paying twice for a single health cover.

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