Declaring crypto in France: boxes 3AN, 3BN, 3CN, annex 2086 and the foreign-platform account

In short

If you are a French tax resident and you sold cryptocurrency for euros or another ordinary currency during the year, the gain has to be declared. Swapping one cryptocurrency for another does not create tax by itself. A separate obligation is to report an account on a non-French platform, and that one applies whether you sold anything or not.

First, work out how the tax office sees you

Since 1 January 2023 the regime depends on your status.

A private individual managing their own assets — the ordinary case. The gain is taxed under the single flat-rate levy (PFU) at 31.4 %: 12.8 % income tax plus 18.6 % social contributions. The number of transactions in the year makes no difference.

A professional — if you buy and resell as a commercial activity (then it is BIC), or carry out operations "in conditions similar to a professional activity" (then BNC). The second covers people making numerous and sophisticated operations throughout the year with the same tools as professional traders. The income is then taxed on the progressive scale plus contributions, with either a 34 % allowance (micro-BNC) or actual expenses.

Mining and staking fall under BNC — a separate category, not a disposal gain.

What counts as a disposal and what does not

Operation	Taxed now
Crypto → euros or another ordinary currency	Yes, the gain is taxed
Crypto → crypto, with no cash balancing payment	No, tax is deferred (sursis d'imposition)
Paying for goods or services in crypto	Yes, that is a disposal too
Moving between your own wallets	No, not a disposal

The €305 threshold is not measured on the gain

The exemption applies when the total of the sale prices for the year does not exceed €305. That is the gross proceeds of all disposals, not the gain, and deferred swaps do not count towards it. Once you are over the threshold, tax applies from the first euro of gain, not only on the excess.

When the progressive scale is cheaper

You may give up the flat rate and choose the progressive income-tax scale instead by ticking box 3CN. Two properties of that choice are worth knowing in advance:

• it is definitive for that return;
• it is separate from the same choice for investment income (interest, dividends) — these are two independent ticks.

The rules provide for both routes; which one costs less depends on your marginal rate, and that is worth computing before you file, not after.

Where each figure goes

The operations are itemised in annex 2086, and the total goes on the main return.

Online. At step 3, click "Déclarations annexes" and add annex 2086. The amount entered there fills box 3AN (gain) or 3BN (loss) on the main return automatically.

On paper. The gain goes in box 3AN of return 2042 C (the supplementary one). A loss goes in box 3BN. The itemised operations are still filed in annex 2086.

A loss offsets very little

A loss can be set only against gains of the same kind in the same year. It cannot be set against gains on other assets, and it is not carried forward to later years — which is where it differs from losses on securities.

An account on a non-French platform is reported separately

Any individual holding a digital-asset account on a platform outside France must report it. For most people that is simply the normal situation: Binance, Coinbase and Kraken are non-French platforms.

• filing online, those accounts are entered at the very end of the procedure;
• on paper, via form 3916-3916 bis, attached to the income tax return.

This obligation stands on its own. It is not cancelled by having sold nothing, nor by staying under the €305 threshold.

Before you file

1. Export the year's transaction history from each platform — you will need it for annex 2086.
2. Separate sales for ordinary currency from crypto-to-crypto swaps: the latter do not enter the gain calculation now.
3. Add up the sale prices and compare the total with €305.
4. List every account held on a non-French platform — for 3916-3916 bis.
5. Compute both routes, the flat rate and the scale, before ticking 3CN.