Solar and wind energy costs have dropped exponentially since a decade ago, to the point where even if the author is correct about the German costs being 3 times more expensive than the French costs, wind and solar will be cheaper than nuclear today, since their costs have reduced dramatically in the last decade. Utility scale solar, for example, is about 90% cheaper today than it was in 2009 when Germany started building out the bulk of its solar energy infrastructure.
In other words, with no other differences, simply the drop in prices of wind and solar means that wind/solar built out today would be about 2-3 times cheaper than France’s nuclear buildout.
Of course, other things have indeed changed since France started building out its nuclear infrastructure. Primarily, nuclear’s negative learning curve has kicked in to the point that even after adjusting for inflation, nuclear today is far more expensive than nuclear when France built out the bulk of its nuclear energy.
Finally, Germany is not even close to the best candidates for solar and wind energy, whereas France is one of the best candidates for nuclear (by definition, it’s one of 10 or so possible candidates, and any new state is likely to be worse at nuclear than France was).