With the massive complement required to run a Nimitz, it would be cheaper for the French to pay full price for a QEC/CVF and run that for say 20 years, than get a Nimitz free and do the same, i.e. I doubt that the French Navy could afford to run a Nimitz.

ETA – too slow

Not only that, but the French use much different reactor technology than we or the RN use. French use lower grade fuel with a more rapid refueling cycle.