Crypto accounting problems often begin well before year-end: an omitted wallet, unreconciled fees or a personal transaction mixed with company activity. Records become more reliable when each movement can be connected to its owner, counterparty and supporting evidence.
These ten mistakes concern French companies and the controls that help address them. Identify the entity’s tax regime and the accounting framework for the financial year before choosing a treatment. A platform or software report does not replace that assessment.
1. Applying individual tax rules to a company subject to corporation tax
The neutrality of certain crypto-to-crypto exchanges under Article 150 VH bis of the French Tax Code belongs to the relevant individual tax regime. It must not be carried over to a company subject to corporation tax. For that company, an exchange requires recognition of the asset leaving and the asset received, with the accounting and tax effect determined accordingly.
Conversely, not every movement creates a profit. A transfer between two wallets owned by the same company may change neither ownership nor the asset’s cost. Classify purchases, sales, exchanges, transfers and income before calculating the result. Read Article 150 VH bis, in French.
2. Mixing personal and company wallets
A wallet used for several owners complicates ownership evidence and transaction analysis. A director controlling a key does not, by itself, prove that every asset belongs to the company. Identify dedicated business addresses and document contributions, repayments and other transactions involving the director.
If assets are already mixed, begin with an inventory and transaction reconciliation. Do not retrospectively treat the entire wallet as company property without evidence. Business account exports and funding records help reconstruct the position.
3. Losing visibility by asset and custody location
A euro total is insufficient to verify quantities. Track assets by token, network and custody location through subaccounts or a subsidiary register reconciled to the general ledger. The level of detail depends on volume and software; the objective is traceability, not unnecessary accounts.
For an asset held on two platforms and one wallet, reconcile each location first and then the total. Blocked, lent or pledged assets should be distinguishable from immediately available holdings.
4. Choosing a valuation because it produces a preferred result
Consistency is necessary, but it does not make an unsuitable method acceptable. Apply the relevant accounting rules, use reliable information and document the date, time, price source and approach to illiquid markets.
ANC Regulation 2026-01 applies mandatorily to financial years starting on or after 1 January 2027, with early adoption permitted for the year in progress at publication on 3 September 2026. For assets within account 522, it requires year-end market valuation using transitional accounts and the prescribed treatment of unrealised losses. This is not a universal rule to put every movement through profit or loss. Read our ANC explanation and implementation dates.
5. Omitting fees or always adding them to acquisition cost
Collect network, trading and custody fees, including those paid in a different crypto-asset. Track the quantity consumed and its value, then apply the treatment appropriate to the transaction.
ANC Regulation 2026-01 expressly requires ancillary acquisition expenses for assets within Article 619-10 to be recognised as expenses according to their nature. It is therefore incorrect to say that all gas fees always form part of acquisition cost. The year’s applicable framework and the asset category determine the method. Consult the ANC texts, in French.
6. Closing an account before exporting its history
Before closing or migrating an account, download orders, transactions, deposits, withdrawals, fees, rewards and balance statements. Keep original files in a controlled location with the period covered and export date. An API connection that works today does not guarantee access to the same data tomorrow.
Check the contracting entity and its authorised services as well. The end of the French MiCA transitional period in July 2026 makes this particularly relevant. Moving to another provider must not erase acquisition-cost evidence. Understand the CASP and MiCA framework.
7. Treating all stablecoins alike
“Stablecoin” describes a stability objective, not a single accounting category. Identify the token’s rights and legal classification. Under ANC Regulation 2026-01, e-money tokens as defined by MiCA fall within account 513; other crypto-assets follow the provisions matching their characteristics.
A dollar-referenced token also presents an exchange-rate issue in euro accounts. Accounting classification does not turn a stablecoin into a bank deposit automatically covered by a deposit guarantee. Document the exact token, issuer, redemption rights and restrictions.
8. Confusing the invoice, payment and conversion
A €10,000 invoice may be settled in crypto, with provider fees and a subsequent conversion. Those stages should not be replaced by the net amount reaching the bank. Reconcile the receivable, quantity received, valuation, fees and any disposal.
If settlement does not cover the whole invoice, identify why: company-borne fees, an agreed adjustment, a partial payment or an error. Electronic invoicing does not remove the need for reconciliation. See our guide to electronic invoicing and crypto payments.
9. Assuming the platform makes every required declaration
A provider’s reporting and its client’s obligations are separate. Article 1649 bis C of the French Tax Code covers, among other things, references of relevant crypto portfolios opened, held, used or closed with foreign organisations by persons or legal entities domiciled or established in France. Check where the actual contracting entity is established.
DAC8 collection covers 2026, with the first data exchanges in 2027; it does not replace your own filings. Review the scope, procedures and evidence for each obligation, including where no disposal occurred. Read the current Article 1649 bis C, in French.
10. Waiting until year-end to investigate discrepancies
Regular reconciliation helps identify incomplete exports, duplicate transactions and unknown counterparties earlier. A quarterly review may be a starting point for modest activity; frequent flows can justify monthly or more frequent checks.
Software supports collection, but classifications need review. A “deposit” is not necessarily income and a “withdrawal” is not necessarily a sale. Maintain a discrepancy list recording the amount, missing evidence, responsible person and resolution status.
A useful check on a randomly selected transaction
Can you find its date, owning entity, asset and quantity, origin, destination, economic purpose, value and supporting record? Can you then explain how it reconciles to closing balances? Any missing step identifies an organisational issue to resolve.
Can an incomplete history be reconstructed?
That depends on the data still available. Some transactions can be corroborated using statements, invoices or blockchain records; others may remain insufficiently documented. We identify those limitations and possible corrections without presenting an incomplete history as fully reconciled.
Explore our crypto accounting approach or tell us about your records. Begin with a list of business accounts and wallets and available exports; do not send private keys or recovery phrases to the firm.