You are British, you live in France or you are over for the weekend, and the evening ends with handcuffs: a fight outside a bar in Paris, a drink-driving check on the road to your Dordogne second home, a misunderstanding at the airport, a fraud allegation at work. The police take you to the station, lock the cell door, and start speaking fast French. Everything you assume from television about English custody — the caution, the custody sergeant, the solicitor on the phone within the hour — stops applying. France has its own machinery, called the garde à vue, police custody, run by a custody officer under a prosecutor, with its own clock, its own list of rights, and its own remedies. Brexit changed nothing about that machinery, but it changed your position inside it: you are now a third-country national, your consulate has a defined role, and any criminal record can affect your residence card, your travel and your insurance. This guide explains, in order, how long the French police can hold you and who controls the clock, which rights the custody officer must read to you at once including the lawyer, the interpreter, the doctor, the family and the consulate, what the prosecutor decides when custody ends, and how you get an unlawful custody annulled, appeal a conviction, and get consular and legal help as a British national. Readers stopped at the roadside before any arrest should also read our companion analysis of when licence exchange is compulsory, what the one-year deadline really means and how to challenge a refusal, and anyone hurt in the same incident should read the insurer offer, the fault trap and how to challenge from the UK.

I. How long can the French police hold you after an arrest, and which rights must they read to you at once?

A. When custody starts, what justifies it, and how the 24-hour rule works

French police custody is not an informal wait in a corridor. Article 62-2 of the Code of Criminal Procedure defines it as a measure of constraint decided by a judicial police officer, under the control of the judiciary, by which a person against whom there are “une ou plusieurs raisons plausibles de soupçonner qu’elle a commis ou tenté de commettre un crime ou un délit puni d’une peine d’emprisonnement”, one or more plausible reasons to suspect that she has committed or attempted to commit a serious crime or an imprisonable offence, is kept at the investigators’ disposal. Two consequences follow that surprise British readers. First, custody is legally impossible for a minor contravention, the lowest class of French offence punished only by a fine, such as a simple parking matter: the suspected offence must carry imprisonment. Second, custody must be the only way to reach at least one of six exhaustively listed aims: carrying out investigations that need your presence, bringing you before the prosecutor so he can decide what follows, stopping you altering evidence, stopping you pressuring witnesses or victims, stopping you conferring with accomplices, or stopping the offence itself. The custody officer, the officier de police judiciaire, decides on his own initiative or on the prosecutor’s instructions, and he must tell the procureur de la République, the public prosecutor, from the start of the measure. If none of the six aims genuinely requires keeping you, the measure has no legal basis, and that defect becomes your first ground of challenge later.

The clock is the second shock. The official Service-Public guide states it plainly: custody lasts 24 hours, and those 24 hours run from the very moment you are detained, sometimes by force. Arrested on the street on Monday at 3 p.m. and driven to the station at 4 p.m., your custody ends on Tuesday at 3 p.m., not 4 p.m. For drink-driving, the starting point is the hour of the breath or saliva test; where you are put in a sobering cell first, the clock starts when you are placed there, whatever time the officer later announces the custody. Nothing about being British, holding a Withdrawal Agreement card or owning a French home pauses or shortens that clock, and nothing about speaking no French extends it: the custody officer must notify you of your placement immediately, in a language you understand, delaying only where the situation on the ground makes immediate notification impossible, for example an arrest on the public highway.

Renewal, the prolongation, is possible but fenced. It requires an offence punished by at least one year of imprisonment, it must again be the only way to reach one of the original aims, and it adds 24 hours, making 48 in total. The prosecutor orders it in a flagrant or preliminary inquiry, the investigating judge in a judicial investigation, and you can put observations to that magistrate, in person or by video link, or dictate them into an interview record sent to him if you are not brought before him. For serious crime the machinery goes further, to 72 hours in total, 96 for drug trafficking or aggravated murder, and 144 for terrorism, ordered by the investigating judge or the liberty and custody judge, the juge des libertés et de la détention. Every extra hour must be justified on paper, and every missing justification is a potential nullity. Practical point for the family telephoning from London: ask the station for the exact hour of the arrest, the legal classification retained, and whether a renewal has been ordered and by whom. Those three facts determine everything that follows.

B. The rights the custody officer must read to you at once, in a language you understand

Article 63-1 of the Code of Criminal Procedure requires the custody officer to inform you immediately, “dans une langue qu’elle comprend”, in a language you understand, where necessary with the standard written form, of your placement and its duration with possible renewals, the suspected classification with date and place, the reasons for holding you, and the full list of your rights. Where you do not understand French, those rights must be notified through an interpreter, if need be after handing you the form for immediate information, and a written statement of the rights is handed to you. The record of the notification goes into the custody log and you countersign it, with any refusal noted. That notification is the hinge of the whole custody: an unrecorded or untranslated notification poisons the hours that follow, because nothing done afterwards can retrospectively inform you.

The lawyer comes first in practice. Article 63-3-1 provides that “Dès le début de la garde à vue et à tout moment au cours de celle-ci, la personne peut demander à être assistée par un avocat désigné par elle ou commis d’office”, from the start of custody and at any moment during it, you can ask for a lawyer you choose or a court-appointed duty lawyer, the avocat commis d’office. Once requested, you are heard only in the lawyer’s presence unless you waive it. If your chosen lawyer cannot be reached or cannot attend within two hours, the custody officer calls the Bar president, the bâtonnier, for a duty appointment. On arrival the lawyer speaks with you privately for up to 30 minutes, sees the custody notification record, your interview records, any medical certificate and any confrontation records, attends every interview and takes notes. Article 63-4-1 adds that “Il ne peut en demander ou en réaliser une copie. Il peut toutefois prendre des notes”, he cannot demand or make a copy, but he can take notes, and on renewal he gets a fresh 30-minute interview with you. British readers should grasp the difference from England: there is no police-station legal-advice fixed fee scheme you recognise, the duty lawyer is arranged through the Bar, and anything you say before the lawyer arrives, apart from stating your identity, can still be used, so the single most valuable sentence in your limited French or English is that you want a lawyer and will otherwise stay silent.

The interpreter is your second shield and it is a statutory right, not a favour. Article 803-5 states that “S’il existe un doute sur la capacité de la personne suspectée ou poursuivie à comprendre la langue française, l’autorité qui procède à son audition ou devant laquelle cette personne comparaît vérifie que la personne parle et comprend cette langue”, where there is doubt about your ability to understand French, the authority must check that you speak and understand it. The Service-Public guide confirms that a person who does not master French has the right to an interpreter in a language she understands, including by telephone or video link. Exceptionally, essential documents can be explained by oral translation or oral summary. Never sign a French record, a procès-verbal, you have not understood: ask for the interpreter, dictate corrections, and refuse to countersign what was never translated. An interview conducted in French with a Briton who plainly did not follow it is challengeable, and the custody log should show when the interpreter was called and what was translated.

The remaining rights complete the picture. Article 63-2 lets you have a partner, relative, person you designate or employer told by telephone, and provides that “Lorsque la personne gardée à vue est de nationalité étrangère, elle peut faire contacter les autorités consulaires de son pays”, where you are a foreign national, the consulate of your country can be contacted. Steps must be taken within three hours of your request unless impossibly prevented, and the prosecutor can defer family or employer notification to protect evidence or people, but never the consular one beyond 48 hours without a judge. You can be examined by a doctor at any time, and your family or the person notified of your custody can demand one too. You can read the custody log, your interview records and any medical certificate at the earliest opportunity and at the latest before any renewal. And at every interview, after stating your identity, you may speak, answer or stay silent. For a British detainee the consular call matters practically: the British guidance confirms that the authorities should ask whether you want the British Consulate contacted, and must do so if you do, with arrest notifications to the consulate normally going out within 24 hours and only where you have asked for the consulate to be informed. Ask expressly, on the record, from the start.

II. What happens when custody ends, and how do you challenge it as a British national?

A. Release, immediate trial or remand: the prosecutor’s choice and your Paris practicalities

Custody ends one of two ways. Either you are released, free or with a later court date, or you are transferred from police premises to the court, the défèrement, to be brought before the prosecutor or the judge who decides the next step. The official guide requires that presentation to happen on the very day custody ends: that presentation must happen on the very day custody ends. If same-day presentation is impossible, you can be held in a court cell for no more than 20 hours after custody ends. The British information pack for France describes the same fork in plain terms: at the end of custody you are either released without charge or presented to the prosecutor, who decides whether to remand you pending investigation or trial, send you to court for an immediate hearing, the comparution immédiate, or release you pending a later hearing with notice of the date, and you keep the interpreter and the lawyer at every stage.

Each fork carries different dangers for a Briton. Release can be clean, or coupled with a summons, a convocation, a penal order you must oppose within its deadline, or a fixed-composition procedure, the composition pénale, whose acceptance can stain your record: never sign a proposal at the station without the lawyer reading it first, because some outcomes create a criminal record entry, the casier judiciaire, that later surfaces on residence and naturalisation checks. Immediate trial means you appear the same day before the criminal court with the file the prosecutor has just built from your custody interviews, and you can ask for time to prepare your defence, which the court can grant with interim conditions. Remand, the détention provisoire, needs a judge and reasoned grounds such as flight risk, and your British address, or lack of a French one, will be discussed openly, so have proof of your French home, lease, tax notices and family ties ready through your lawyer. Where the case is serious, an investigating judge, the juge d’instruction, is appointed and the questioning restarts under his control, with your lawyer present and the file accessible.

Paris and Ile-de-France add local texture worth knowing in advance. Custody business for the capital concentrates around the Paris police headquarters and the Paris judicial court, the tribunal judiciaire de Paris, on the island in the centre, with the liberty and custody judge sitting there for renewals beyond 48 hours and for remand decisions. The Paris Bar runs a criminal duty scheme, and the British Embassy consular section sits at 35 Rue du Faubourg St Honoré, 75008 Paris, telephone +33 (0)1 44 51 31 00, covering Paris, the northern regions and the overseas territories, with working hours 9 a.m. to 5 p.m. Monday to Friday and round-the-clock backup through the Foreign Office in London on +44 (0)20 7008 5000. Keep those two numbers in your telephone under recognisable names before any trouble, because a mobile seized at the station leaves you with nothing but memory. And one Brexit-specific warning: where you have no right to remain in France, an arrest can trigger the immigration track alongside the criminal one, with administrative detention, the rétention administrative, of up to 90 days in a detention centre while return to the United Kingdom is arranged. A Withdrawal Agreement holder or visa holder should have the lawyer put the residence permit and passport copies before the prosecutor at once, to keep the two tracks separate.

B. Getting the custody annulled, appealing the conviction, and getting help as a Briton

French law annuls an irregular custody through nullities, the nullités. Article 171 of the Code of Criminal Procedure states that “Il y a nullité lorsque la méconnaissance d’une formalité substantielle prévue par une disposition du présent code ou toute autre disposition de procédure pénale a porté atteinte aux intérêts de la partie qu’elle concerne”, there is nullity where disregard of a substantial formality required by the Code or any criminal-procedure provision has harmed the interests of the party concerned. Harm, the grief, is therefore the key: a late notification, an interpreter never called though you plainly did not follow the French, a lawyer requested but never alerted, an interview started during the two-hour wait without written prosecutorial authority, a renewal ordered by the wrong magistrate or a search or bodily examination ordered unlawfully can all support annulment where they prejudiced you. Raise nullities early, before any defence on the merits, through the lawyer, at the trial court or, in an investigation, before the investigating chamber, the chambre de l’instruction. Annulment of the custody can carry away the acts that flow from it, including confessions and sometimes seizures, which is why prosecutors fight these applications hard.

The proof battle turns on paper, and a recent Court of Cassation ruling sets the terms. On 6 May 2025 the Criminal Chamber, appeal No. 24-86.191, ECLI:FR:CCASS:2025:CR00550, decided a case where a man placed in custody after a road check had asked from the start for the lawyer of his choice, and the investigating chamber had annulled the custody for want of diligence records. The Court restated the rule in terms every custody file must now be measured against: “Il résulte de ces textes que l’officier de police judiciaire établit un procès-verbal récapitulatif de fin de garde à vue mentionnant les informations données et les demandes faites en application des articles 63-2 à 63-3-1 du code de procédure pénale et les suites qui leur ont été réservées, sans qu’il soit nécessaire de dresser un procès-verbal pour chacune des diligences accomplies pour l’exercice de ces droits.” A single end-of-custody summary record covering the notifications, the requests and what became of them suffices; no separate record is needed for each step. Applying that rule, the Court held: “En statuant ainsi, alors qu’il résulte des pièces de la procédure, dont la Cour de cassation a le contrôle, que l’officier de police judiciaire a, dans le procès-verbal récapitulatif de fin de garde à vue, fait état des diligences accomplies à la suite de la demande faite par la personne placée en garde à vue pour s’entretenir avec l’avocat qu’elle avait choisi dès le début de la mesure, et des suites qui y avaient été données, la chambre de l’instruction a méconnu les textes susvisés et le principe ci-dessus énoncé” The result followed: “CASSE et ANNULE, en toutes ses dispositions, l’arrêt susvisé de la chambre de l’instruction de la cour d’appel de Paris, en date du 7 octobre 2024, et pour qu’il soit à nouveau jugé, conformément à la loi. The lesson cuts both ways for your case. Where the summary record genuinely traces each request to its outcome, courts will now forgive the absence of intermediate records. Where the summary is silent or contradictory on the lawyer, the interpreter or the consular call, the defence case for harm is stronger than before, because the ruling confirms exactly what the record should have contained.

Conviction is not the end either. The British pack summarises the French appeal ladder accurately: after sentence, an appeal can be lodged by either the defendant or the state prosecutor within ten working days, in writing through the court clerk, the greffe, or the lawyer, and the prosecutor-general has up to two months. Appeal re-tries the case before the court of appeal, and it can delay release, so take advice before lodging it. After a re-trial, a five-calendar-day window opens to take the case to the Supreme Court of Appeal, the Cour de Cassation, which sits in Paris and judges only errors of law or procedure, never the facts. Separately, ill-treatment or discrimination in custody can be raised through complaints to the police authorities with consular support, and plainly unlawful detention can go before the liberty judge. On money, two cushions exist: the consulate supplies a list of local English-speaking lawyers and interpreters and general information on legal aid, while France runs its own means-tested scheme, the aide juridictionnelle, described on the official legal-aid page, which a duty lawyer can trigger for you. Understand lastly what the consulate will and will not do. The Foreign Office formula is honest: consular staff will do what they can to help, but they cannot interfere with the local justice system, get anyone out of jail, or pay for a lawyer, and no British passport buys special treatment in a French prison or court. What they can do is visit or telephone, check you are treated to recognised standards, tell the doctor of medical needs with your permission, pass money from your family, link you with the charity Prisoners Abroad, and help with transfer to a British prison in some cases. The lawyer fights the case; the consulate keeps you human inside it. Instruct the first on day one, call the second on day one, and make both calls appear in the custody record.

Conclusion

French police custody is a short, sharp, paper-driven procedure: plausible suspicion of an imprisonable offence and a single listed aim justify it, the 24-hour clock runs from the moment you are held, one 24-hour renewal needs a year of threatened imprisonment and the right magistrate, and the officer must tell you at once, in a language you understand, that you can have a lawyer from the start, an interpreter throughout, a doctor, a call to your family or employer and to your consulate, sight of the key records, and silence after your identity. When custody ends you leave free, or you walk to the court the same day toward immediate trial, a later summons or a remand judge. Where any link in that chain breaks to your prejudice, the nullity action, the appeal within ten working days and the five-day Cassation appeal are your remedies, and the May 2025 ruling on the end-of-custody summary record tells your lawyer exactly which paper to attack. Ask for the lawyer, ask for the interpreter, ask for the consulate, sign nothing untranslated, and get every request written into the record: those four reflexes decide more cases than any argument afterwards.