France's Finance Committee backs taxing Bitcoin-to-USDC swaps before any cash-out

Under French tax authority guidance, a covered crypto-to-crypto exchange with no cash balancing payment gets tax deferral today ^[3]. How large the new bill gets therefore depends on a second part of the text, the cost basis deducted from the proceeds.

Take the hypothetical investor in CryptoSlate's example: Bitcoin that cost €20,000 and is worth €60,000, Ether that cost €40,000 and is worth €40,000, so €60,000 of cost against a €100,000 portfolio ^[12], with no prior disposals, fees or cash balancing payments and unchanged euro values ^[14]. On evidenced actual cost, swapping all the Bitcoin into USDC recognizes a €40,000 gain ^[15]. The allocation route spreads the old-rules cost pool across holdings in proportion to Dec. 31, 2026 values ^[8]. On it, Bitcoin is 60% of value and takes €36,000 of basis ^[13], so the same swap recognizes €24,000 ^[16], or €16,000 less ^[17]. Ether runs the other way. Its allocated basis is €24,000 ^[18], a €16,000 gain ^[19] where actual cost gives none ^[20]. Sold in full, the portfolio shows a €40,000 gain on either route ^[21].

The choice is irrevocable for the whole portfolio once the first return reporting a taxable disposal after Jan. 1, 2027 is filed ^[9]. In our view the swap into USDC is a likely candidate for that return, since the swap itself would be a taxable disposal ^[4]. The investor would then pick a route before knowing which asset they sell next, and the example shows the stakes: a wrong guess recognizes €16,000 more gain on the first sale ^[17][19], though the €40,000 total does not move ^[21]. The evidenced route also requires evidence ^[8], so an investor without purchase records would, on the wording, be left with allocation.

Two other terms bear on a swap at a loss. Taxable swaps would reset the basis of the tokens received, and existing rules would still stop net crypto losses offsetting gains in later years, according to CryptoSlate's summary ^[7]. On that summary, a loss realized on a swap into USDC would give no relief against later gains.

The thesis depends on the legislative process. The exception is one clause in a broader overhaul of how private crypto gains are calculated ^[1], and it applies from Jan. 1, 2027 only if enacted ^[2]. CryptoSlate's account does not describe the stages between the committee vote and enactment. A final text without the exception would leave the swap deferred under today's guidance ^[3].