A nation made a bet on "let's do all nuclear". It basically worked, but there was no magical cost decrease. They have an immense amount of institutional knowledge, huge educational system, massive amounts of resources. Their nukes are big and expensive and not really on time. There is no magic at the end of the tunnel if Greenpeace disappears.
The world isn't Sim City, power plants need water access and have location concerns, and it's not a question of just dropping a bunch of truck-sized plants across the world and magically solving everything.
Having said that, France is a success story of course. It's cool that it's all set up. But even after building it up, running these plants are expensive, there's often load issues meaning they are not fully utilized... "nuclear is free easy energy" is science fiction. That's fine, though! It's normal that we have to do stuff to power society.
EDIT: to be clear, I'm cool with nuclear, but I am not picky about where my watts come from.