Since the rapid emergence of crypto-assets, the French tax authorities have implemented specific tools for declaring capital gains realized upon their disposal. Form 2086, introduced as part of the income tax return, is the official document used to detail these transactions. Correctly completing this form is essential to comply with regulations and optimize your tax situation.
Crypto-assets, such as Bitcoin (BTC) and Ethereum (ETH), are subject to the capital gains regime on digital assets under Article 150 VH bis of the French General Tax Code (Code général des impôts, CGI). The complexity lies in the precise calculation of taxable capital gains, notably due to the "single disposal" rule and the need to establish a weighted acquisition cost. Furthermore, operations involving NFTs (non-fungible tokens) and DeFi (decentralized finance) introduce additional specificities.
Calculation of Crypto Capital Gains: Principles and Method
The calculation of taxable capital gains on crypto-assets follows the formula:
Capital gain = Sale price – Weighted acquisition cost
This method is mandated by the French Tax Administration (source: Official Bulletin of Public Finances - BOFiP, BOI-IR-DGT-20-20-20-10).
The sale price corresponds to the total amount received during the sale or exchange of crypto-assets, expressed in euros at the time of the transaction. The weighted acquisition cost is the average weighted by the number of crypto-assets acquired, including acquisition fees.
Single Disposal Rule: Explanation and Implications
The so-called "single disposal" rule means that during a disposal, the crypto-assets sold are considered to come from a global pool of held assets. The acquisition cost calculation is therefore performed on the total units held, weighting their purchase price accordingly. This rule prevents the selection of a specific lot (FIFO or LIFO method), which can significantly impact the declared capital gain.
For example, if an investor acquired 1 BTC at €20,000 and then 0.5 BTC at €25,000, their weighted average cost is:
Quantity (BTC)
Unit Price (€)
Total Cost (€)
1.0
20,000
20,000
0.5
25,000
12,500
Total
32,500
Weighted average cost = €32,500 / 1.5 BTC = €21,666.67 per BTC.
If the investor sells 1 BTC at €30,000, the capital gain is:
€30,000 - €21,666.67 = €8,333.33 taxable.
Filling Out Form 2086: Steps and Best Practices
Form 2086 consists of several sections designed to collect the following information:
Details of disposal transactions (date, sale price, any fees)
Calculation of capital gains or losses per transaction
Overall summary of net capital gains to be reported on the main tax return (Form 2042 C).
It is crucial to keep an accurate history of all transactions, especially to calculate the weighted average cost in accordance with the single disposal rule. Exchange platforms often provide detailed statements, but it is recommended to use crypto portfolio management software to ensure data reliability.
Cases of NFTs and DeFi: Tax Specificities
NFTs and DeFi operations represent specific cases in Form 2086 declaration:
NFTs: Non-fungible tokens are considered digital assets. Their disposal is subject to the same tax regime as other crypto-assets. The sale price corresponds to the consideration received in euros or crypto-assets valued in euros at the date of the transaction. The acquisition cost corresponds to the initial purchase price of the NFT.
DeFi: Decentralized finance operations, such as yield farming, swaps, or loans, can generate taxable capital gains or income. Exchanges between crypto-assets via smart contracts are considered disposals, triggering a declaration obligation. Form 2086 must therefore include these operations with precise valuation in euros.
For example, an exchange on a DeFi platform of 2 ETH acquired at €1,500 each against 0.05 BTC (value of 1 BTC = €30,000 at the time of exchange) must be declared as a disposal of 2 ETH (weighted acquisition cost) with a sale price equivalent to €1,500 (0.05 BTC × €30,000).
Numerical Examples: Bitcoin and Ethereum
Example 1 - Bitcoin Sale:
Date
Operation
Quantity (BTC)
Unit Price (€)
Value (€)
01/01/2021
Purchase
1.0
20,000
20,000
01/06/2021
Purchase
0.5
25,000
12,500
01/12/2021
Sale
1.0
30,000
30,000
Weighted average cost = €32,500 / 1.5 BTC = €21,666.67 per BTC
Capital gain = €30,000 - €21,666.67 = €8,333.33
Example 2 - Ethereum Sale:
Date
Operation
Quantity (ETH)
Unit Price (€)
Value (€)
15/02/2022
Purchase
10
2,500
25,000
10/08/2022
Sale
5
3,000
15,000
Weighted average cost = €25,000 / 10 ETH = €2,500 per ETH
Capital gain = (5 × €3,000) – (5 × €2,500) = €15,000 – €12,500 = €2,500
Official Sources and Recommended Tools
The official texts to consult for Form 2086 declaration are:
Official Bulletin of Public Finances (BOFiP): BOI-IR-DGT-20-20-20-10 (https://bofip.impots.gouv.fr)
Official website of the Tax Administration (impots.gouv.fr)
INSEE for economic indices, Banque de France for historical exchange rates (https://www.banque-france.fr)
To facilitate declaration management, several specialized software (CoinTracker, Koinly, Accointing) allow automatic import of transactions and generation of reports compliant with Form 2086. These tools are valuable for avoiding errors and tax audits.
Conclusion: Recommendations for French Investors
Declaring capital gains on crypto-assets via Form 2086 is an essential step for every investor. Compliance with the single disposal rule and use of the weighted acquisition cost ensure a compliant and optimized declaration. Investors should:
Maintain rigorous tracking of all their transactions
Accurately value each operation in euros, especially in NFT and DeFi cases
Use specialized tools to automate calculation and completion of Form 2086
Anticipate payment of the flat tax (PFU) of 30% applicable on capital gains
By following these best practices, investors reduce the risk of tax reassessment and better control their tax burden. The increasing complexity of crypto-asset operations requires heightened vigilance and systematic recourse to specialized advice if necessary.
