French crypto holders face an irrevocable cost-basis choice under a draft stablecoin swap tax

The amendment's explanatory statement makes a narrow case. Under current rules, it argues, holders can move an appreciated bitcoin or ether gain into a fiat-backed token without paying the tax a direct sale for currency would trigger ^[10]. The fix is just as narrow. It removes the exemption only where the holder receives an electronic money token as the EU's MiCA regulation defines one ^[9], so on this text France leaves other crypto-to-crypto swaps alone. Once a swap is taxable, the gain is the disposal value minus the acquisition cost, with documented transaction fees deducted ^[11].

The cost-basis options for coins bought before 2027 are where the holder actually has a choice, as crypto.news described the amendment text ^[12]. Under the allocation option, each coin's assigned cost is the portfolio's total acquisition cost multiplied by that coin's share of portfolio value on December 31, 2026. Divide both sides by the coin's value and every coin carries the same cost-to-value ratio as the whole portfolio ^[16]. A holder with thin records gets a usable basis. In a portfolio that is in profit overall, a coin bought near a top loses its embedded loss, because the blend gives it the same gain ratio as everything else ^[16].

Daniel Labaronne's amendment, I-CF798, changes what that embedded loss is worth ^[14]. With losses currently lapsing at the end of the tax year ^[15], a documented loss on a losing coin had value only in a year with winners to absorb it. A 10-year carry-forward stretches that window from a single tax year to a decade ^[17]. If both amendments pass, a holder who takes the allocation option for convenience gives up deductions that the second amendment makes portable.

If the swap tax passes without Labaronne's change, a holder converting a mixed portfolio into stablecoins in 2027 can net losses only against that year's gains ^[15]. Both could also stall. The committee adopted the swap tax on October 7 ^[3], and it, the loss relief and the exit tax all need further parliamentary approval, with the January start date subject to that process ^[6]. Crypto Briefing likewise described the measures as not yet enacted ^[2].

I think the decision to make before January 2027 is about records more than rebalancing. A 2026 swap into a stablecoin keeps today's deferral ^[8], but it postpones only the tax that a later conversion to currency would trigger anyway ^[10]. It also changes what sits in the portfolio on December 31, 2026, the date the allocation option values ^[12]. The case against that view is a holder who wants long-term dollar or euro exposure and never plans to cash out. For that holder a pre-2027 swap avoids a tax that would otherwise arrive with the swap itself ^[1]. That case depends on the amendment passing with its date intact, and if the date slips or the text is dropped ^[6], waiting would have cost nothing.