It would, of-course, be legal, should anybody present a mechanism for it to become so.
The French agent did it and the result is that the IC-A6FR with DGAC approval costs 649 euros. The only difference is an aerial with an FM filter, which, of course, cannot be bought separately. Looks like a protectionist scheme to me.
ICOM FRANCE : Produits Radiocommunication : Aviation Portatifs : IC-A6FR
ICOM FRANCE : Produits Radiocommunication : Accessoires Platines et filtres : FL-IFFM1