Trading bots are fast; tax administrations are patient. A grid bot can close hundreds of taxable events in a year, and the French tax system wants each one accounted for in euros. If you are a French tax resident running automated strategies, this guide explains the framework as it stood in early 2024 — what is taxed, at what rate, and which records keep you safe.
A necessary caveat: this is general information, not tax advice. Crypto taxation in France has changed repeatedly and will change again. Confirm the current rules with the tax administration’s official documentation or a professional before filing.
The flat tax, in one paragraph
For most private, occasional crypto investors, capital gains on digital assets are taxed under the flat-tax regime: 30% total — 12.8% income tax plus 17.2% social contributions — on the taxable gain, after an annual allowance of €305 on the total of disposals. The gain is calculated in euros, per disposal, at the moment it happens. You do not owe tax on unrealized gains: a portfolio that doubles and is never sold triggers nothing.
Occasional investor or habitual trader?
The flat tax applies to occasional activity. Cross the line into habitual trading — activity that is frequent, sophisticated, leveraged, or effectively a principal source of income — and gains can be reclassified as industrial and commercial profits, taxed at progressive income-tax rates plus contributions. There is no bright-line test; frequency, leverage, skill and dependence on the income are weighed together. Running a bot is not automatically professional, but running many bots at high frequency with leverage is exactly the profile that invites the question. If your activity is large or leveraged, get a professional opinion before the administration forms its own.
Every disposal is an event — and bots dispose constantly
Two things create taxable events: selling crypto for euros (or any fiat), and exchanging one crypto for another. That second point surprises bot users: every ETH→BTC rebalance, every grid sell into USDT, every swap a strategy executes is a disposal with a gain or loss attached — even if you never touch euros. A single grid bot cycling through a range twice a day generates hundreds of line items per year. Plan your record-keeping for that volume from day one, not in April.
How the gain is actually calculated
The standard formula uses a prorata of your total acquisition cost: the taxable gain on a disposal equals the sale price minus the fraction of your portfolio’s total cost that corresponds to the portion sold. Worked example:
| Line | Amount | Note |
|---|---|---|
| Portfolio value before sale | €50,000 | All digital assets, valued in euros |
| Total acquisition cost | €30,000 | Everything you paid to build the portfolio |
| Amount sold | €10,000 | One disposal into euros |
| Cost attributable to the sale | €6,000 | 30,000 × (10,000 ÷ 50,000) |
| Taxable capital gain | €4,000 | 10,000 − 6,000 |
| Flat tax at 30% (before allowance) | €1,200 | Less any available annual allowance |
The formula rewards one behavior above all: keeping complete cost records. Without them, you cannot defend the cost basis — and the default assumption is rarely in your favor.
The records that keep you safe
- A complete export of every trade: timestamp, pair, quantities, euro value at execution, fees.
- Deposits and withdrawals, so transfers between your own wallets are provable and not mistaken for disposals.
- A consistent valuation method applied all year — do not switch mid-year between “reasonable” valuations.
- Bot configuration exports, so automated activity can be reconciled with exchange statements.
- Everything kept for the full retention period — tax administrations look back years, not months.
Three ways traders actually handle it
| Approach | Cost | Effort | Error risk |
|---|---|---|---|
| Spreadsheet | None | Very high with bots | High — hundreds of events |
| Crypto tax software | Low annual fee | Low — imports via API/CSV | Medium — check the mappings |
| Accountant | Highest | Lowest | Lowest — and defensible |
For anything beyond a handful of manual trades per year, software that imports your history is close to mandatory; a professional becomes worthwhile as volumes grow or the habitual-trader question gets closer.
Losses and edge cases
Capital losses on digital assets do not carry forward to future years under the flat-tax regime — they can only offset gains realized during the same year, which is one more reason to review your realized P&L before December 31 rather than after. Rewards from staking or lending have their own treatment and reporting obligations, and newer regimes (for platforms and certain services) have been layered on since 2023. These are precisely the details that change — verify the current version of the rules rather than relying on any article, including this one.
The flat tax is simple. The record-keeping is not. The traders who pay the least are rarely the ones who found a loophole — they are the ones who kept the best books.
The bottom line
If you are a French tax resident running bots: assume every sell and every swap is taxable at 30% on the euro-denominated gain, keep transaction-level records from the first trade, reconcile before year end, and involve a professional the moment your activity starts to look habitual. The automation should live in your trading — never in your assumptions about the taxman.
Alleen educatieve inhoud — geen financieel, fiscaal of juridisch advies. Prestaties uit het verleden, reëel of historisch, bieden geen garantie voor toekomstige resultaten.
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