Crypto Capital Gains: 7 Common Mistakes in 2026 Reporting
Reporting cryptocurrency capital gains is not just a matter of adding up profits and entering an amount on your tax return. Between non-taxable exchanges, the specific calculation of profits, and the forms to fill out, several pitfalls can lead to tax errors. Even occasional investors are affected. To avoid any unpleasant surprises, here are the seven most common mistakes in the 2086 declaration, along with the rules to know and the best practices to adopt.
Sponsored content by Brisbane Media. The editorial team did not participate in the creation of this article.
Key Takeaways
- Crypto-to-crypto exchanges without an additional payment benefit from a tax deferral, unlike purchases of goods or services in cryptocurrencies.
- The tax exemption threshold of €305 applies to the total annual disposals of the tax household, not the gains.
- The taxable capital gain is calculated using a global formula that includes the entire portfolio.
- Schedule 2086 details the transactions, while boxes 3AN and 3BN reflect their annual result.
- Crypto losses can only offset capital gains of the same nature realized during the same year.
- The flat rate reaches 31.4%, with an option to choose the progressive scale via box 3CN.
- Accounts held on foreign platforms must be declared using form 3916-bis.
Mistake #1: Considering all cryptocurrency transactions as taxable
Purchasing Ethereum with Bitcoin does not automatically trigger a tax liability. In France, exchanges between digital assets without additional monetary consideration benefit from a tax deferral, according to Article 150 VH bis of the General Tax Code (CGI).
Specifically, converting BTC to ETH without receiving an additional sum in euros does not immediately generate a tax. Taxation occurs during a subsequent taxable sale.
However, using cryptocurrencies to buy a computer, book a hotel, or pay for a service constitutes a taxable transaction. Therefore, it's not necessary to convert assets into euros to trigger taxation. This distinction requires special attention with crypto payment cards, which can automatically convert assets at the time of purchase.
The BOFiP outlines the transactions covered by this regime.
Mistake #2: Believing the €305 Threshold Applies to Profits
The threshold of €305 is often misunderstood. It does not represent the maximum amount of exempt profits, but rather the total sales prices achieved during the year by the entire household for tax purposes.
Let's consider an example: You sell cryptocurrencies for €400 with only a €20 profit. The threshold is exceeded, even if your gain is small. Conversely, three sales of €100 each represent €300 in sales. They are exempt, regardless of the gain realized.
Be careful: when the threshold is exceeded, taxation applies to the capital gains from all taxable sales of the year, not just the portion above €305. Even below this threshold, the sales prices of exempt transactions must be reported on form 2086.
Mistake #3: Calculating Crypto Gains Separately for Each Asset
Unlike traditional stocks, cryptocurrencies held in a private capacity are subject to a global calculation method.
Article 150 VH bis of the French General Tax Code provides the following formula: Capital gain = Sale price − (Total acquisition price × Sale price ÷ Total portfolio value). This formula considers all digital assets held at the time of each sale, including those kept on other platforms or personal wallets.
Imagine a portfolio with a remaining total acquisition cost for tax purposes of €6,000, with a current value of €10,000. You make a sale of €2,000. The calculation gives: 2,000 − (6,000 × 2,000 ÷ 10,000), resulting in a capital gain of €800. This example assumes no fees and no previous transactions affecting the fiscal capital.
After each sale, the remaining acquisition capital must be updated. Therefore, it is essential to maintain a history of transactions and portfolio valuation.
Mistake #4: Incorrectly Filling Annex 2086 and Forgetting Boxes 3AN/3BN
Reporting crypto income involves several steps. Form 2086 is used to detail taxable disposals made during the year, while the main declaration summarizes their overall result.
To report crypto capital gains, it is necessary to provide information on the sale prices, the portfolio values, and the calculated gains or losses.
Online, the 2086 form is accessible from additional declarations. The result is usually automatically carried over:
- Box 3AN: annual net capital gain.
- Box 3BN: annual net capital loss.
For paper declarations, these amounts are reported on the additional form 2042 C, accompanied by form 2086. Each relevant transaction must be detailed, not just the balance shown by a platform.
Mistake No. 5: Believing Crypto Losses Can Be Carried Forward
A year with a deficit does not allow for the creation of a reserve of tax losses that can be used later. Losses on digital assets can only be offset against gains of the same nature made during the same year.
For example, a gain of €1,500 and a loss of €900 realized during the same fiscal year result in a net taxable gain of €600. However, a net loss of €2,000 cannot reduce gains made the following year. It also cannot offset a real estate or stock market gain that falls under another tax regime.
To avoid mistakes, it's better to prepare a complete annual report before filling out the tax return, rather than focusing only on winning transactions.
Error #6: Applying the Wrong Tax Rate or Checking Box 3CN Without Verification
For sales made as part of the management of a private estate, the flat-rate levy (PFU) is 31.4%, broken down as follows:
- 12.8% income tax.
- 18.6% social contributions.
A net taxable capital gain of €1,000 therefore represents €314 in taxation at the flat rate.
However, there is an alternative: opting for the progressive income tax scale by checking box 3CN. This option is explicit and irrevocable for the applicable year. It applies to all crypto gains of the household, but is independent of the 2OP option related to investment income.
This option may be advantageous for certain low-taxed taxpayers. A preliminary simulation can help compare the two options, keeping in mind that social contributions are still owed.
Mistake #7: Failing to report accounts on foreign platforms
Declaring gains is not enough. Digital asset accounts opened, held, used, or closed with foreign-based entities must also be reported to the tax authorities. This obligation particularly applies to accounts on international platforms, even when no taxable sale has been made.
The declaration is completed using form 3916-3916 bis, in addition to the annual income tax return. Failure to declare can result in a fine of up to €750 per undeclared account. This rises to €1,500 when the value of the accounts exceeds €50,000 at any point during the year.
To avoid oversight, verify the country of establishment for each platform used and keep records of your accounts, including those that have become inactive.
A reliable crypto declaration is prepared throughout the year. Transaction history, acquisition proofs, portfolio valuation, and identification of foreign accounts are the essential components of a solid dossier. By gradually collecting these elements, you simplify completing appendix 2086 and reduce the risk of errors. In complex situations, particularly with numerous transactions or multiple platforms, the guidance of a tax professional can also be beneficial.
Contenu conçu et proposé par Brisbane Media. La rédaction n'a pas participé à la réalisation de cet article.
This content has been automatically translated using artificial intelligence. While we strive for accuracy, some nuances may differ from the original French version.
