You'd think he would of got that call up if he hadn't been injured recently. His form can't of gone unnoticed.
I don't know how big the talent pool is at U21 level but Lyon alone consistently produce good young players. Add to that Clairefontaine and the other federation academies, it's no surpise they have been a very competetive team over a long period.
As above, he must be on their radar though, particularly having played at other youth levels. Do they want/need his type of player? Selections certainly become more narrow as you move up through the youth teams, U21s essentially being groomed for the senior team.