Poor French, then, especially if ID checking is not a SkyTeam thing but a mandatory government rule. Who knows more?

Obviously, ID checks make sense for AIRLINES in order for them to make sure that the person who bought a restricted/cheap/nonrefundable ticket (now very popular in Europe) is travelling on it, and not somebody else (like a friend or family member). But these checks, if they occur, have nothing to do with security. Btw, even in the USA, you don't need an ID for domestic flights. However, w/o ID, you'll have to undergo additional screening. So my guess would be, if you declined to show your ID in France, you would still be able to fly. Well, try that next time (by pretending to have fogotten your ID) on a domestic flight and tell us about the reaction.