Fintech and crypto lawyer Paris

A fintech lawyer acts on the client's side. Firms that describe themselves in this way most often assist companies in the sector with their authorisation applications. The position of a saver, a craftsman or an association is different: an account closed without explanation, a payment you did not intend, a platform that no longer replies, an investment whose capital has vanished. These disputes fall under the Monetary and Financial Code, contract law and, for individuals, consumer law.

The first task is to characterise the transaction. A payment transaction is authorised if the payer has consented to its execution (Article L. 133-6); if it is not, the provider must refund it no later than the end of the first business day after it is reported (Article L. 133-18). If it is, the client must prove a fault by the provider under ordinary law.

The firm then examines the time limit still open, the identity and status of the provider, and the documents the provider holds. It can draft the complaint, refer the matter to the competent mediator or bring the action, indicating at each stage what the case law accepts and what it refuses.

For an open-ended deposit account, the law requires the credit institution to give at least two months' notice, served on paper or another durable medium (Article L. 312-1-1). The courts do not agree on whether this provision applies to legal entities acting for their business.

The Paris Court of Appeal set aside the statutory period for a company's business account, while holding that "closure may take place only on giving sufficient notice, allowing the client to contract for new banking services, which is assessed in particular by reference to the size of the client company and the nature of its business" (CA Paris, pôle 5, ch. 6, 21 February 2024, No. 21/14330) (our translation). It added that "the decision to close the account need not be reasoned and is therefore discretionary" (CA Paris, pôle 5, ch. 6, 21 February 2024, No. 21/14330) (our translation). It nevertheless awarded compensation to an estate agency whose thirty-day notice was insufficient given the volume of its business, and dismissed the claims of the other companies.

The Montpellier Court of Appeal, for its part, applied the two-month notice to a company but dismissed its claim for failure to prove the loss caused by the closure (CA Montpellier, ch. com., 4 November 2025, No. 24/04741), an unfavourable outcome. From the closure letter onwards, the file must therefore include proof of the rejected payments and lost contracts. A company domiciled in France that has no account may also request the right to an account (Article L. 312-1).

The general terms of payment providers and marketplaces almost always provide a power of suspension. The Court of Cassation has held, in relation to an online listing service, that by providing for a suspension clause on legal grounds and then applying it to a misleading site, "a host does not create a significant imbalance within the meaning of Article L. 442-6, I, 2°, now Article L. 442-1, 2° of the Commercial Code" (Cass. com., 4 September 2024, No. 22-12.321) (our translation). The outcome is unfavourable to the suspended company, whose business was held to be unlawful for lack of authorisation. This solution, specific to a host required to remove unlawful content, does not carry over of its own accord to a payment provider.

The position of an individual is different. In a contract concluded with a professional, a clause that creates, to the detriment of the consumer, a significant imbalance between the parties' rights and obligations is unfair (Article L. 212-1 of the Consumer Code). A clause allowing a consumer's funds to be blocked without notice or reason can be challenged on that ground.

In both cases, the firm reads the clause relied on, checks the notification and the reason alleged, then examines separately the basis for suspending the service and that for withholding or returning the balance, depending on the provider's status. The claim may then concern the return of the balance rather than the resumption of the relationship.

Almost everything. The refund as of right, within the business day following the report, applies only to unauthorised transactions (Article L. 133-18). If the transaction is authorised, the client can obtain compensation only by proving a fault by the provider, most often a breach of the duty of vigilance.

The dividing line is severe for businesses. In a fake-executive fraud, transfers ordered by an employee who believed she was obeying a director were held to be authorised, the judgment noting that they had been made by the employee "believing she was acting on the instructions of one of the directors, through the secure payment system made available by the bank" (Cass. com., 30 April 2025, No. 24-11.255) (our translation). The company's appeal to the Court of Cassation was dismissed.

Deception as to the person giving the order is therefore not enough to make the transaction unauthorised. The firm checks who actually validated the order, with what authentication device, and whether an authorised person was consulted. Where the transaction is authorised, it examines in particular the apparent anomalies that the bank holding the account could have detected, the basis accepted in the cases cited, without ruling out claims against the other parties involved.

The decisions cited here did not take that view. The Court of Cassation holds that "the banker's duty of non-interference in a client's affairs yields, by virtue of the duty of vigilance, only where there is an apparent anomaly" (Cass. com., 2 May 2024, No. 22-17.233) (our translation). In that case, the unusual amount of a transfer was not enough, the client being himself its economic beneficiary.

The trial courts apply this rule strictly to fraudulent investments. For a saver approached by telephone who had transferred almost all of their savings to a trading platform, the Paris Court of Appeal upheld the dismissal of their claims, recalling that "the client is at liberty to dispose of their savings as they see fit, even if that means drastically changing their habits and management choices" (CA Paris, pôle 5, ch. 6, 12 November 2025, No. 23/17193) (our translation). The decision is unfavourable to the saver.

The remedy is not closed, however. The Court of Cassation accepts that the bank's liability may be sought for breach of vigilance where the transfers are authorised (Cass. com., 12 June 2025, No. 24-13.697). It is then necessary to show an anomaly that was apparent to the bank on the date of the order, on the basis of the information it held. The beneficiary's appearance on the AMF blacklist may be an indication, provided it predates the transfers: in the case decided by the Paris Court of Appeal, it came later and the saver's claim was dismissed (CA Paris, pôle 5, ch. 6, 12 November 2025, No. 23/17193).

No, on the ground of civil liability. Regulated financial institutions exercise constant vigilance over the business relationship (Article L. 561-6), enhanced where they consider the risk of money laundering to be high and in the other cases provided for by the legislation (Article L. 561-10-1). Fraud victims often invoke these provisions to argue that the fraudster's account should never have been opened or credited.

The Court of Cassation has closed this route. It holds that this duty of vigilance has the sole purpose of combating money laundering and terrorist financing and that, consequently, "the victim of fraudulent acts cannot rely on their non-observance to claim damages from the financial institution" (Cass. com., 4 March 2026, No. 24-19.588) (our translation). In that case, the judgment that had ordered the bank to pay on this basis was quashed, a solution unfavourable to the client.

The argument must therefore be replaced by others. For an unauthorised transaction, the special regime of the Monetary and Financial Code applies. For an authorised transaction, the route examined in the decisions cited is that of the apparent anomaly. The position of the bank that opened the beneficiary's account is examined separately, in light of the documents obtained.

It can raise the point. The payer bears all losses caused by unauthorised transactions where they failed, intentionally or through gross negligence, to keep their personalised security data safe (Article L. 133-19; Article L. 133-16).

The assessment remains fact-specific. The Court of Cassation quashed a court of appeal that had ruled "on a peremptory ground excluding the payer's gross negligence where approached by a telephone call from a person presenting themselves as an employee of the payment service provider" (Cass. com., 9 September 2026, No. 25-15.038) (our translation). The client who had disclosed their credentials and validated transactions they had not initiated lost the benefit of the judgment, an unfavourable outcome.

The account of the fraud therefore matters as much as the rule. Number displayed, information already known to the fraudster, messages received from the bank, exact nature of what was validated: the firm reconstructs the chronology minute by minute before answering the bank's refusal. The law also excludes any loss for the payer where the provider did not require strong authentication, except in the case of fraudulent conduct (Article L. 133-19, V).

Not necessarily. The user must report an unauthorised or incorrectly executed transaction without delay, and at the latest within thirteen months of the debit, on pain of time bar. But the same provision allows the parties to agree a different period, except where the user is an individual acting for non-professional purposes (Article L. 133-24). The account agreement of a company, a craftsman or an association may therefore provide for a shorter period.

The first check concerns this point. The firm reads the business account agreement and its schedules to identify the period that actually applies, then compares it with the date of the debit and that of the first written report.

Once the report has been made within the period, the court action is no longer confined to the thirteen months. The Court of Cassation so held in quashing a judgment that had declared the action time-barred: the account holder who reported the transaction in time "may bring an action for reimbursement against the payment service provider within the ordinary limitation period" (Cass. com., 1 July 2026, No. 25-16.495) (our translation), provided they reported the transaction without delay once they became aware of it. The ordinary limitation period for a personal action is in principle five years (Article 2224 of the Civil Code).

It depends on the service concerned. For crypto-asset services, the principle is authorisation as a provider by the Financial Markets Authority (Autorité des marchés financiers) under the European MiCA Regulation, but some entities that are already regulated proceed by notification and some offers of electronic money tokens are not subject to authorisation; the AMF publishes the list of authorised providers (Article L. 54-10-7). For the investment service of underwriting, authorisation falls to the Prudential Supervision and Resolution Authority or, for portfolio management companies, to the Financial Markets Authority (Cass. com., 9 July 2025, No. 23-15.492).

The Court of Cassation clarified the effect of lack of authorisation for the investment service of underwriting. Disregard of it "is capable of engaging the civil liability of the person who provided that service where it causes its counterparty a personal and direct loss resulting from the deprivation of the safeguards attached to the authorisation of investment service providers, it cannot have the effect of rendering the contracts concluded null" (Cass. com., 9 July 2025, No. 23-15.492) (our translation). The claim for nullity had been rejected. This decision does not rule on a crypto-asset services contract subject to the MiCA Regulation, nor on other grounds of nullity: whether it can be transposed must be argued case by case.

Within the framework of that judgment, the client must show the personal and direct loss arising from the deprivation of the safeguards attached to authorisation. The firm first checks the provider's status on the date of each transaction against the authorities' public lists, then chooses the legal basis and the sanction suited to the applicable regime.

In principle yes, if they are a consumer domiciled in France. Investment platforms established outside the European Union often insert a clause giving jurisdiction over disputes to a court in their own country. The Court of Cassation holds that, under the principles of French private international law, "a consumer domiciled in France on the date of the document initiating proceedings cannot be deprived, by a jurisdiction clause designating a foreign court, of the right to bring the matter before the French courts" (Cass. 1re civ., 7 October 2026, No. 25-14.323) (our translation). The appeal brought by the professionals was dismissed.

Two conditions must be checked. First, consumer status, which was not disputed in the case cited and is assessed by reference to the investor's activity. Second, domicile, assessed on the date of the writ of summons, at the place of the main establishment. In the judgment cited, the Court approved the judges for having established that domicile from concrete documents: invoices, statements, registration on the electoral roll.

The firm gathers this evidence before serving the writ of summons, then examines enforcement of the decision against a foreign provider, a question distinct from jurisdiction.

The ordinary limitation period is five years from the day the holder knew, or should have known, the facts enabling them to exercise their right (Article 2224 of the Civil Code). The provider often argues that it started at signature, when the saver could have read the documentation.

The Court of Cassation adopts a different date where the complaint concerns the information given about the risk of loss. It holds that "the limitation period for an action for compensation for such a loss cannot begin to run before the date on which the investment was lost" (Cass. com., 21 May 2025, No. 24-13.217) (our translation). The judgment that had declared the action time-barred by using the date of the contracts was quashed, in the saver's favour.

This solution protects the saver whose investment collapses several years after subscription. It does not remove the need to prove the date of the loss: liquidation judgment, valuation statement, letter announcing the end of repayments. Referral to the mediator of the Financial Markets Authority also suspends the limitation period during the mediation (Article L. 621-19).

It depends on the security subscribed. Where the investor bought bonds, they belong to a bondholders' group (masse). The representatives of the group, authorised by the general meeting of bondholders, alone have standing to bring actions for the defence of the bondholders' common interests, and any contrary action is declared inadmissible of the court's own motion (Article L. 228-54 of the Commercial Code).

The Court of Cassation applies this rule even to preparatory measures. It held that a request for an expert assessment or for production of documents before any trial, where it concerns all the subscribers, "may be brought only by the representative of the group authorised by the general meeting of bondholders" (Cass. com., 9 October 2024, No. 23-10.645) (our translation). The investor's appeal was dismissed, an unfavourable outcome.

A loan is not the same as a bond: intermediation in loan-based crowdfunding has its own regime, which excludes in particular activities falling under the 2020 European regulation on crowdfunding service providers (Article L. 548-1). Who may act then depends on the platform's regime, the contract and the powers given to the platform to claim the sums due. The firm first identifies the nature of the security, the platform and the representative of the group, then chooses between collective action, filing a proof of claim and a personal claim.