You settled in France after Brexit, kept your HSBC or Lloyds current account in London, left your Cash ISA where it was, and still hold Premium Bonds bought years ago. The British bank calls the ISA interest tax-free and National Savings & Investments describes Premium Bond prizes as tax-free in the United Kingdom. None of those labels decides your French position. Once you are fiscally domiciled in France, the French tax administration, the Direction générale des finances publiques (DGFIP, the French tax authority), taxes your worldwide income, requires a separate declaration of every foreign account on Form 3916, and applies a 1,500-euro fine per undeclared account. A dormant account you have not touched for three years, a joint account with a parent, or an ISA you thought was invisible because it is sheltered in Britain can each generate its own fine.
This article is written for a British reader living in France. Every French term is explained at first use. It covers which British accounts and products must be declared, how France taxes the interest and prizes that Britain exempts, where the France-United Kingdom double tax treaty of 19 June 2008 helps and where it does not, what happens when the tax office discovers an undeclared HSBC or Barclays account through automatic exchange of information, and how to regularise the file and challenge fines and back-tax bills before the tax office and the administrative court, the tribunal administratif (the first-instance court for tax disputes). It finishes with the Paris and Ile-de-France practical points: which office holds your file, which court hears your appeal, and what to prepare before you walk in.
I. What France taxes and what you must declare when you live in France with UK accounts
A. Which British accounts trigger Form 3916 and the annual income returns?
The starting point is fiscal domicile. Article 4 A of the French General Tax Code provides: “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 terms, a person whose tax home is in France pays French income tax on worldwide income, not only on French-source income. Article 4 B of the same Code sets three alternative tests for a French tax home: the home or principal place of stay is in France, a professional activity is carried on in France unless it is merely ancillary, or the centre of economic interests is in France. Meeting any one of the three is enough, subject only to the tie-breaker of an applicable double tax treaty. A British national who rents or owns a flat in Paris, whose children attend a French school, and who spends most nights of the year in France will normally satisfy the first test even if the salary or pension is still paid into a London account.
Once French fiscal domicile is established, the declaration duty is separate from the payment of tax. Article 1649 A of the General Tax Code states: “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.” Every word of that sentence matters for a British household. The duty covers accounts opened, held, used or closed abroad during the year, and it applies to each account separately. A current account at HSBC UK, a savings account at Nationwide, a Cash ISA at Virgin Money, a Stocks and Shares ISA platform account, Premium Bonds held with NS&I, a joint account shared with a mother in Manchester, and an e-money account with Wise or Revolut that holds sterling for more than a passing transfer can each fall inside the perimeter when the holder is domiciled in France.
Three misunderstandings cause most British files to fail. First, dormancy is not an exemption. An account you have not touched for two years but have not closed remains held and must be declared again each year until closure is declared. Only the year in which you declare the closure ends the cycle, and the closed account must still be listed for that year. Second, a nil balance is not an exemption. The form asks for the references of the account, the bank, and the dates, not for a minimum balance. Third, the British tax wrapper does not travel. A Cash ISA remains a bank or savings account in French eyes, Premium Bonds remain a foreign capitalised product, and a Junior ISA opened for a child remains reportable by the parents when the child is attached to their French tax household, the foyer fiscal (the group of persons taxed together in France). The official guidance on the service-public.fr page on declaring foreign accounts confirms that foreign bank, savings and investment accounts must be declared at the same time as the yearly income return, using Form 3916, known as Cerfa 11916, and that each account is declared individually.
In practice the yearly routine has three layers. Form 3916 lists each foreign account with the bank name, address, account number, opening date and, where relevant, closing date. Form 2047, the return for foreign-source income, reports the interest, dividends and prizes account by account. Form 2042, the main income return, carries the totals into the French calculation. A British resident who declares the interest on Form 2047 but forgets Form 3916 has paid the tax but still committed the declaration offence, and the 1,500-euro fine can still be imposed. Conversely, filing Form 3916 without reporting the interest on Form 2047 cures the disclosure fine but leaves the income assessment open. Both layers must be correct every year, including the year of arrival and the year of departure, with the dates of residence properly stated.
Joint accounts deserve particular care. Where a British resident in France shares an account with a parent who stayed in England, the French holder must declare the whole account, not a half share, because the declaration duty attaches to the holding, not to the beneficial split. The taxable interest may then be apportioned according to who funded the account and who received the interest, with bank statements and a written explanation kept in the file. The same logic applies to an account on which the French resident holds only a power of attorney, a procuration (a written authority to operate someone else’s account): the implementing rules treat an account as used as soon as the person has carried out at least one credit or debit transaction, whether as holder or by proxy. A daughter in Lyon who pays her late father’s English bills from his account after his death should therefore keep the death certificate, the grant of probate, and the closing statements, and take advice on whether the estate period creates its own filing position rather than assuming the account can simply be ignored.
Digital accounts complete the picture. A sterling balance held with a British e-money institution, a PayPal balance used for a small online business, or a crypto platform account that also holds cash balances can be caught by the same duty when the operator habitually receives deposits. The test is functional, not the marketing label. When in doubt, British residents in France should declare the account: an unnecessary 3916 line costs nothing, while a missing line costs 1,500 euros per account per year and opens the door to a wider enquiry into the origin of the funds.
B. How France taxes the interest and prizes that Britain calls tax-free?
French tax residence brings worldwide interest and investment income into the French base. Article 120 of the General Tax Code treats dividends, interest and similar products of foreign shares and claims as income within its scope, including interest on foreign bank and savings accounts. UK bank interest, Cash ISA interest, and distributions inside a Stocks and Shares ISA therefore enter the French taxable base even though HM Revenue & Customs, usually shortened to HMRC, the British tax authority, charges no tax inside the ISA wrapper. Premium Bond prizes are analysed in France as investment income or prizes linked to a capitalised product rather than as a tax-exempt windfall: the British exemption described on the NS&I Premium Bonds page and the yearly allowance described on the gov.uk ISA page operate only for British tax. They do not bind the DGFIP. A British resident in France who omits ISA interest or Premium Bond winnings on the ground that no British tax was due makes the most common and the most expensive error in these files.
The France-United Kingdom double tax treaty of 19 June 2008, published in English on gov.uk among the France tax treaties, allocates the right to tax interest principally to the state of residence, with a limited residual withholding tax permitted at source in defined cases. For a British national resident in France, that means France taxes the interest and eliminates double taxation by credit where British tax was correctly levied, rather than by exempting the income. In the ordinary British savings case there is no British tax to credit, because the ISA or the personal savings allowance reduced the British bill to nil, so the French charge applies in full. Where British tax was actually withheld, for example on certain bonds or on interest paid without treaty relief at source, the treaty credit mechanism prevents the same pounds being taxed twice, but the taxpayer must prove the British levy with certificates and statements. A British bank’s generic annual summary is rarely enough on its own; the file should contain the gross interest per account, the British tax actually deducted, and the treaty article relied upon, translated into the boxes of Form 2047.
The rate then depends on the French regime for capital income. Article 200 A of the General Tax Code sets the default flat-rate levy, the prélèvement forfaitaire unique (a single flat-rate charge on capital income, commonly called the PFU or flat tax), at 30 per cent in total, comprising 12.8 per cent income tax and 17.2 per cent social charges, the prélèvements sociaux (French social levies charged on capital income alongside income tax). UK bank and ISA interest reported by a French resident normally falls within this 30 per cent charge unless the household validly opts for the progressive scale, the barème progressif (taxation at the graduated income-tax rates), under the option provided by the same article. The option is global for the year across the relevant capital income and must be exercised expressly in the return; it cannot be applied account by account after the event. Households with little other income sometimes gain from the progressive scale, while higher-rate households usually pay less under the flat rate, but the comparison must be made on the full French return, including the 17.2 per cent social charges which apply in most cases even when the income-tax element falls under the option.
Two further French layers regularly surprise British readers. First, interest paid through a French paying agent is subject to a mandatory withholding at source during the year, the prélèvement forfaitaire non libératoire (an advance withholding credited against the final bill), governed by Article 125 A of the General Tax Code, whereas interest paid directly by a British bank into a London account is received gross and settled entirely through the French assessment the following year. The absence of a withholding is not an exemption; it simply defers the full charge to the avis d’imposition (the final tax bill). Second, the 17.2 per cent social charges apply to most investment income of French residents regardless of the income-tax option, subject only to the European coordination rules for persons affiliated to another state’s social security system. A British retiree holding a valid S1 healthcare certificate and affiliated to the British system may have a distinct position on social charges that must be evidenced year by year; a British employee affiliated in France will normally bear them in full. Files that copy the British net figure into the French return without adding back the social charges systematically underpay.
Currency and evidence complete this part. Interest must be converted into euros at the rate applicable to the year of receipt, with the rate and method stated consistently across years. The administration accepts the European Central Bank reference rates or the Bank of France rate when applied consistently, but it rejects files that mix spot rates on favourable days without explanation. Keep the British statements in pounds, a conversion schedule in euros, the ISA annual summaries showing the wrapper, the NS&I prize vouchers or annual prize statements, and proof of any British tax withheld. Where the Stocks and Shares ISA holds funds that distribute dividends, each distribution keeps its dividend character in France even though it remains inside the ISA; the wrapper does not convert a dividend into exempt interest. Where the ISA holds accumulating units, the undistributed income may still be taxable on distribution or disposal depending on the product, and the platform’s consolidated tax certificate must be read line by line rather than copied as a single figure.
II. The 1,500-euro fines and how to regularise and challenge them in Paris and Ile-de-France
A. Where the fine comes from and what the tax office must prove?
The fine is not discretionary in its trigger, though its application can be challenged on its conditions. Article 1736, section IV, of the General Tax Code provides: “Les infractions aux dispositions du deuxième alinéa de l’article 1649 A et de l’article 1649 A bis sont passibles d’une amende de 1 500 € par compte ou avance non déclaré.” Each undeclared account therefore generates its own 1,500-euro fine for each year concerned, and the same paragraph continues: “ce montant est porté à 10 000 € par compte non déclaré lorsque l’obligation déclarative concerne un Etat ou un territoire qui n’a pas conclu avec la France une convention d’assistance administrative en vue de lutter contre la fraude et l’évasion fiscales permettant l’accès aux renseignements bancaires.” The United Kingdom has concluded such an assistance convention with France and participates in the Common Reporting Standard, the automatic exchange of bank information between tax authorities, so the ordinary British case stays at 1,500 euros per account rather than 10,000 euros. The exchange itself is the reason most British files are detected: every year HMRC transmits the balances and interest of French residents’ British accounts to the DGFIP, and the computer comparison with Forms 3916 produces the enquiry.
The procedural path usually follows three letters. First, a request for information and justifications on foreign assets, often based on Article L.23 C of the Tax Procedures Book, gives the taxpayer sixty days to explain the origin of the funds and the use of the account. Second, an inadequate reply leads to a formal demand to complete the answer within thirty days. Third, persistent silence or insufficient justification allows the administration to assess the account balance itself through the taxation-of-office procedure, the taxation d’office (an assessment the administration raises on its own figures when the taxpayer has not provided sufficient answers), with the burden then shifting to the taxpayer to prove the assessment excessive. Alongside the income assessment, the 1,500-euro fines per account are notified in the penalty notice, the avis de mise en recouvrement (the formal demand for payment of tax and penalties).
The courts apply this chain strictly, as two recent decisions show. In a judgment of 7 May 2026 concerning an undeclared British HSBC account, the Versailles judicial court recalled the exact declaration rule: “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.” The case is published at Tribunal judiciaire de Versailles, 7 May 2026, no. 23/07001. The file had been opened after information received from the British and Maltese tax authorities about accounts held in those states. The administration had assessed the highest balance of the British HSBC account at 365,272.51 euros and taxed half of it in the hands of the French Eduardo resident spouse at 60 per cent, sending a recovery notice for 109,582 euros in registration duties. The court rejected all of the taxpayer’s claims, holding that inactivity of the account after 2018, a declaration filed in 2019, and general statements about the origin of the funds did not displace the assessment where the sixty-day and thirty-day procedure had been followed and the justification remained insufficient. The lesson for British readers is direct: once the exchange data arrives, arguing that the London account was old, dormant, or funded long ago, without bank-by-bank documentary proof of origin, fails.
The second decision confirms that the higher courts will not easily reduce these penalties on proportionality grounds. On 17 September 2025 the Commercial, Financial and Economic Chamber of the Court of Cassation, the Cour de cassation (France’s highest court for civil and criminal matters), rejected an appeal against a Paris Court of Appeal judgment that had upheld assessments raised after Swiss accounts were revealed through a public prosecutor’s transmission: Cass. com., 17 September 2025, no. 23-10.403. The administration had questioned the taxpayers under Article L.23 C of the Tax Procedures Book after receiving account information, and the courts sustained the resulting assessments. British residents should read this as confirmation that the L.23 C enquiry followed by assessment is a standard, court-approved path, whether the account is in Geneva, Malta or London, and that a challenge must attack the concrete steps — residence, account characterisation, amounts, deadlines, or double counting — rather than inviting the judge to waive the mechanism in general.
B. How to fix the file and challenge the bill step by step, including Paris and Ile-de-France practice?
The priority order is simple: stop the accumulation of fines first, then correct the income, then challenge what remains. A British resident who discovers today that three British accounts were never declared should file the missing Forms 3916 for the open years without waiting for the enquiry letter, pay or provision the income tax and social charges on the omitted interest through a corrective return, the déclaration rectificative (an amended return replacing the original figures), and keep proof of spontaneity. Spontaneous regularisation does not erase the 1,500-euro fines already incurred, but it demonstrates good faith, the bonne foi (honest conduct taken into account for penalties and interest), stops further yearly fines from accruing on the same accounts, and deprives the administration of the argument that the taxpayer persisted after acquiring knowledge. The file should state plainly, account by account, when the account was opened, why it was omitted, when it was or will be closed, and what interest and prizes were received each year in pounds and euros. A short covering letter in French, one table per account, and the British statements behind it will do more for the file than a long narrative about Brexit confusion.
Once an assessment or a fine has been notified, the first remedy is the administrative claim, the réclamation contentieuse (a formal written claim to the tax office seeking discharge or reduction of the bill). The claim must identify each assessment, state the grounds account by account, attach the evidence, and be filed within the statutory deadline shown on the recovery notice. The most effective grounds in British-account files are concrete: the taxpayer was not yet or was no longer fiscally domiciled in France in the year assessed, with tenancy agreements, travel records and treaty tie-breaker evidence; the account is not a declarable account, for example a closed-before-residence account with no transaction during the French years, proved by dated closing letters rather than assertions; the same account was counted twice because it changed number when the bank migrated systems, proved by the bank’s migration letter; the interest was already declared and taxed, with Forms 2047 and assessment notices exhibited, so that only the disclosure fine and not the income charge is at stake; the British tax actually withheld was not credited under the treaty, with withholding certificates exhibited; or the sixty-day and thirty-day steps of the L.23 C procedure were not correctly followed, with the envelopes and dates exhibited. General arguments about the modest balance, the absence of fraud, or the British tax-free label do not discharge the 3916 duty and, as the Versailles HSBC case shows, do not displace an assessment based on the highest balance where origin remains unjustified.
Interest for late payment and the income-tax penalties are a second battle from the 3916 fines. The administration often adds a surcharge for undeclared income alongside the per-account fines. Those surcharges depend on good faith and on whether the omission is characterised as deliberate, so the spontaneous filing, the completeness of the tables, and the consistency of the euro conversions feed directly into the outcome. Where the file is coherent, the claim can seek relief on the surcharge even while accepting the corrected base; where the administration maintains the surcharge, the appeal to the administrative court can isolate that point without reopening the whole base. Each euro of penalty must be tied to its legal basis in the response, because the judge will examine them separately.
If the claim is rejected expressly or by silence after six months, the appeal lies to the administrative court. For readers in Paris and Ile-de-France, the map is precise. Residents of Paris itself appeal to the Paris administrative court; residents of Seine-Saint-Denis, Val-de-Marne and Seine-et-Marne appeal to the Melun administrative court; residents of Hauts-de-Seine, Val-d’Oise and Yvelines appeal to the Cergy-Pontoise administrative court; residents of Essonne and the southern departments appeal to Versailles. The tax file itself is usually held by the local public finance centre, the service des impôts des particuliers (the local personal-tax office, known as the SIP), for the address of residence, with the regional directorate, the direction régionale des finances publiques (the regional tax directorate, known as the DRFIP), handling the legal defence once the case is lodged. A Paris file therefore moves from the neighbourhood SIP to the Paris DRFIP and then to the Paris court, while a file in Boulogne-Billancourt or Saint-Germain-en-Laye moves through the corresponding SIP to the Ile-de-France directorate and the Cergy or Versailles court. The appeal must be lodged within two months of the rejection, contain numbered pleas, and exhibit the British statements, the 3916 forms, the 2047 forms, the assessments, the claim and its receipt, and the treaty certificates in chronological bundles. Judges in these courts see dozens of exchange-of-information files each year; a bundle organised account by account and year by year is decided faster and more favourably than a single narrative PDF.
A distinct Paris problem arises when the British bank itself closes the account because the holder now lives in France. Several British banks have restricted or closed retail accounts for customers with only an EU address since Brexit, citing licensing costs. A British resident in France who receives such a closure letter should not confuse the bank’s commercial decision with the French declaration duty: the account must still be declared for every year it was held or closed, and the closure letter is actually useful evidence of the closing date. For day-to-day banking in France, the French right to an account provides a remedy. Article L.312-1 of the Monetary and Financial Code states: “A droit à l’ouverture d’un compte de dépôt dans l’établissement de crédit de son choix, sous réserve d’être dépourvu d’un tel compte en France : 1° Toute personne physique ou morale domiciliée en France”. A person domiciled in France who has been refused an account can apply to the Banque de France, which designates a bank that must open a basic account with defined basic services. The procedure does not reopen the London account, but it secures French banking continuity while the British closure and transfer are documented for the tax file, including the destination of the transferred balance so that no unexplained credit appears on the new statements.
Two final practical points protect Paris and Ile-de-France files. First, never commingle the regularisation money with unexplained funds. Pay the corrective tax from a declared French account by transfer, keep the debit advice, and move the British savings by visible transfer rather than cash withdrawals, so that the administration cannot treat the same pounds as fresh undeclared income. Second, calendar the limitation periods. The administration’s right to reassess is time-limited, and older years fall away when the conditions are met, but a missing 3916 line combined with unreported income can extend the window; the claim should therefore verify year by year that the assessment was raised in time rather than conceding the whole period in one sentence. A taxpayer who concedes 2019 without checking the date of the notice may pay a year that was already out of time.
Conclusion
A British resident in France can keep British accounts, ISAs and Premium Bonds, but cannot keep the British tax treatment of them. France taxes the worldwide interest and prizes, requires Form 3916 for every account held, used or closed during each year of French residence, and fines each missing line at 1,500 euros under Article 1736 while assessing unexplained balances through the L.23 C and taxation-of-office chain that the Versailles HSBC judgment and the Court of Cassation decision of 17 September 2025 have upheld. The treaty prevents double taxation of the same interest through credit, but where Britain charged nothing inside the ISA or on the Premium Bond prize there is nothing to credit and the French charge of 30 per cent, or the progressive scale on express option plus 17.2 per cent social charges, applies in full. The remedy is methodical: declare every account including dormant, joint and closed-in-year accounts, report the interest and prizes in euros on Forms 2047 and 2042, regularise spontaneously before the exchange data arrives where possible, and challenge assessments and fines account by account with bank proof, conversion schedules and treaty certificates, from the administrative claim to the competent administrative court for the Paris or Ile-de-France address. Organised early, a British savings history becomes a routine disclosure; left undeclared until the computer comparison arrives, the same history becomes a 109,582-euro lesson of the kind the Versailles court has already taught.