No, all usage of Cryptocurrency is illegal.

According to the “Journal Officiel” (28 December 2017):

Art. 117. — The purchase, sale, use, and retaining of so-called virtual currency is prohibited. Virtual currency is that used by internet users via the web. It is categorised through the absence of physical aid such as coins, notes, payments by using cheque or deposit card. Any breach of this provision is punishable in accordance with the laws and regulations in force.