Crypto tax audits in France

A French crypto tax audit rarely happens by chance. The tax authorities now have powerful detection tools at their disposal — tools that grow stronger every year:

• Data mining (the CFVR program). The DGFiP (the French tax administration) automatically cross-references tax, banking and asset data to spot inconsistencies — a significant share of audits of individuals already relies on this targeting.
• Online data collection. Since 2020, the administration has been authorized to use public posts on social media and online listings to detect outward signs of wealth inconsistent with declared income.
• Bank flows. A transfer received from an exchange platform, even a single one, is enough to establish a link between your bank account and crypto activity. The administration can obtain this information from banks through its “droit de communication” (statutory right to obtain information).
• Foreign accounts. Accounts opened on platforms established outside France (Binance, Kraken, Coinbase, Bybit…) must be declared every year using form 3916-bis. Failing to declare them is detectable in itself — and penalized.
• DAC8, a change of scale. Since January 1, 2026, exchange platforms (the “PSCA”, crypto-asset service providers) have been collecting the identity, tax residence and transaction history of their users. This data will be transmitted to the DGFiP for the first time on June 15, 2027 (2026 transactions), then exchanged automatically between European Union administrations from September 30, 2027. The OECD’s CARF framework will then extend this exchange to dozens of non-European jurisdictions (United Kingdom, Switzerland, the United Arab Emirates, Singapore…).

In other words: in time, this data will be systematically matched against your tax returns.

Crypto-asset taxation is one of the most complex areas of French tax law. Between specific reporting obligations, capital gains calculation rules, tax regimes that vary with the nature of the transactions (trading, staking, mining, NFTs, etc.) and constantly evolving regulations, it is easy to make mistakes with serious consequences.

A tax lawyer whose practice focuses on crypto-assets brings dual expertise: command of tax law on the one hand, and an in-depth understanding of blockchain technologies and crypto mechanisms on the other. This rare combination is essential to defend your interests effectively before the tax authorities.

Your exchanges with your lawyer are covered by professional secrecy, at every stage. Enforceable against the tax authorities, this protection guarantees the confidentiality of your information. It is essential for handling sensitive tax matters, particularly in the field of crypto-assets.

Every situation is unique. Individual investor, active trader, crypto entrepreneur, blockchain company, DeFi platform: the stakes and the solutions differ radically. A crypto tax lawyer analyzes your situation as a whole to build a tailor-made strategy, whether to anticipate risks, regularize your situation or defend you in the event of an audit.

Penalties in crypto tax matters can be heavy: surcharges of 40% to 80% of the evaded tax, late-payment interest, and even criminal proceedings for tax fraud in serious cases. Expert support helps you anticipate them and limit their impact.

Learn more: crypto lawyer in Paris →

As a rule, the French tax authorities can reassess your returns for the last three years: this is the ordinary limitation period. It is extended to ten years in the situations most frequently seen with crypto: an account held on a foreign platform that was not declared (form 3916-bis omitted), or an “activité occulte” (undisclosed activity), meaning an activity carried on without ever being declared — habitual trading, structured mining, recurring NFT sales. For many holders of never-declared Binance, Kraken or Coinbase accounts, the ten-year period is therefore the one that applies in practice.

Not all letters from the tax authorities carry the same weight. Identifying which procedure has been opened is the first step: it determines your obligations, your deadlines and your safeguards.

The first contact often takes the form of a request for information: a letter asking about your digital-asset accounts or about identified transfers. In principle, this request is not binding, but it is far from harmless: your answer sets the framework for the case.

The request for clarifications or justifications is of a different order: a reply is mandatory, within two months. A missing or insufficient reply can open the way to “taxation d’office” — the administration then assesses your income itself, and it is up to you to prove the assessment is excessive.

The desk audit takes place in the administration’s offices, without your necessarily being informed: the inspector reviews your returns in light of the data available to them (bank flows, platform information, cross-checks). You often only discover it exists when you receive a “proposition de rectification” (reassessment notice) — the document setting out the additional tax and penalties being considered. You then have thirty days to submit your observations, extendable by a further thirty days on request. This adversarial phase is decisive: this is where the amounts, the characterizations and the surcharges are debated.

The ESFP — the adversarial, in-depth examination of your personal tax situation — is the most thorough form of audit for an individual. The administration compares all of your declared income against your actual flows: bank accounts, platform accounts, lifestyle. It lasts one year at most in principle, a period that can be extended to two years, notably where an undisclosed activity or foreign accounts are discovered. The procedure is framed by safeguards (adversarial debate, the audited taxpayer’s charter) that you need to know in order to have them respected. At this stage, a lawyer’s assistance is no longer a luxury: the slightest discrepancy in the reconstruction can translate into an additional assessment.

The financial risk of a French crypto tax audit breaks down into several layers, which must be distinguished to size your exposure correctly:

• Back taxes. The tax and social levies evaded on undeclared gains, recalculated according to the characterization retained (individual capital gains, BNC, BIC).
• Late-payment interest. 0.20% per month, i.e. 2.4% per year, from the date the tax should have been paid.
• 10% surcharge. Error or omission without a deliberate breach.
• 40% surcharge. Deliberate breach.
• 80% surcharge. Undisclosed activity or fraudulent maneuvers.
• Reporting fines (3916-bis). €750 per undeclared account and per year (€1,500 if the account’s value exceeds €50,000), capped at €10,000 per return.
• Criminal exposure. In the most serious cases, the administration can refer the file to the public prosecutor (tax fraud).

Two counterweights, drawn from practice. First, these penalties are not automatic: the surcharge applied depends on how the administration demonstrates your intent — and it can be debated, document by document, from the adversarial phase onwards. Second, good faith and well-managed cooperation are elements the administration takes into account when assessing the file.

What we see in defense work, case after case: it is not always the initial facts that cost the most, but the way the first weeks are handled.

1. Replying too quickly. Under stress, people want to “show goodwill” and reply within the week. Yet every sentence sent to the tax authorities commits you: an approximation, a clumsy characterization (“I did a bit of trading”) can shape the entire case.
2. Providing too much… or not enough. Sending documents that were not requested opens new questions; giving an incomplete reply to a request for justifications exposes you to “taxation d’office”. The scope of the reply has to be calibrated.
3. Reconstructing your flows in a rush. Incomplete exports, miscalculated weighted average acquisition prices, forgotten wallets: an inconsistent history does lasting damage to your credibility. A rigorous reconstruction is, conversely, your best piece of evidence.
4. Ignoring the deadlines. Each letter opens a specific deadline — two months, thirty days… Letting a deadline pass means giving up safeguards, or letting the administration establish its position on its own.
5. Waiting until the litigation stage to get support. Much is decided before any formal appeal: the choice of replies, the dialogue with the inspector, the discussion of the surcharges. The earlier the support begins, the wider the room for maneuver.

First rule: do not reply in haste. The first answer given to the tax authorities often determines the rest of the case. Date the letter, identify the reply deadline and the exact nature of the procedure — and send nothing before you have taken full stock of what is actually being asked of you.

If you have just received a letter, here is the order of operations:

1. Date the letter and note the reply deadline. It is your first constraint — everything else is organized around it.
2. Identify the procedure. Simple request for information, request for justifications, ESFP notice, “proposition de rectification”: the stakes and your rights are not the same.
3. Do not file anything in haste. A “régularisation sauvage” — corrective returns filed in a rush after receiving a letter — can make your situation worse instead of better.
4. Gather the complete history. Exports from every platform (including closed accounts), wallet addresses, bank statements: reconstructing the flows takes time, so start immediately.
5. Size your exposure before replying. Years concerned, applicable limitation period, tax at stake, potential surcharges: you cannot define a reply strategy without knowing what is at stake.
6. Get support from the very first reply. Exchanges with a lawyer are covered by professional secrecy, at every stage.

As long as no procedure has been opened against you, another path remains available: voluntary regularization. Taking the initiative changes the nature of the file — you are no longer a taxpayer under audit, but a taxpayer coming into compliance. In practice, a voluntary approach makes it possible to assert good faith, to request a reduction of the penalties and, under the “droit à l’erreur” (the right to correct in good faith), to benefit from reduced late-payment interest.

Timing matters: the data collected by the platforms since January 1, 2026 will be transmitted to the DGFiP from June 15, 2027. Regularizing before the tax authorities identify you means keeping the benefit of a voluntary approach — and choosing the timing and the conditions of your coming into compliance.

• Your foreign crypto accounts are undeclared (3916-bis): the firm offers dedicated support, with the scope and fees defined in advance.
• An audit is already under way: coming into compliance remains possible during the procedure, within a different framework.

For a simple request for information about a clear-cut situation, it is conceivable. But crypto-asset taxation combines two layers of technicality: the substance (characterization of gains, capital gains calculation, foreign accounts) and the procedure (deadlines, safeguards, burden of proof). Every written answer commits you for the rest of the case — and exchanges with a lawyer are protected by professional secrecy.

A desk audit has no statutory duration: several weeks to several months often pass between the first request and the “proposition de rectification”. An ESFP is limited by statute to one year, extended to two years in certain cases (undisclosed activity, foreign accounts). The full procedure, appeals included, can extend well beyond that.

Yes — and soon automatically. Since January 1, 2026, these platforms have been collecting the identity and transaction history of their European users (the DAC8 directive); the first transmission to the DGFiP will take place on June 15, 2027. And already today, the administration can trace its way back to your accounts through your bank flows and international cooperation.

No. The “proposition de rectification” opens the adversarial phase: you have thirty days — extendable by a further thirty days on request — to submit your observations. This is the stage where the amounts, the characterizations retained and the surcharges are debated, before any appeal to the administration’s senior officials or litigation. Every line of the notice deserves to be analyzed.

At every stage: first request for information, desk audit, ESFP, reply to a “proposition de rectification”, appeals and litigation — as well as upstream, for a preventive review or a voluntary regularization. The earlier the intervention, the more options remain open. Maître Stéphanie Némarq-Attias, a tax lawyer of 17 years’ standing, founded QOMIT specifically to support holders of crypto-assets.