I doubt France would want to leave NATO in that they hold a most advantageous position vis a vis the rest, US included, i.e., France holds a "joker", she is an "insider" but a very independent one.

If you like, they've got it extremely good both ways so why leave? (Actually, this is one of the bones of contention by US delegation -- France has the vote, the "veto" power in NATO but is independent to do as she pleases when she feels like it. Pretty great position to be in, don't you think?