France's nuclear is long paid off, and there were big government investments into building the industry around it because France is a nuclear power. It's not exactly the same tech obviously but when you build nuclear weapons yourself you need a workforce and industry capable of working with the materials. Some of those costs will have found their way under defense headings instead of energy ones.

Germany didn't have this incentive and they don't have the luxury of coasting on previous investments of a bygone era. Germany would have to start from scratch with all this and without the defense component (unless they change their stance on that too)