I already read 2 or 3 book Michio Kaku and I have never been disappointed. It is hard to beat as a popularizer. I'm not sure if his style easily pass in french but the author certainly has very many talents to explain these complicated concepts.
He uses very often very good metaphors to illustrate the theories. His book is the other very well structure which beacoup aid to understanding.
The negative points might be that the author is so enthusiastic that sometimes I have the impression that tries to explain too much in his books. Reading is sometimes so dense that it was not hard to understand but remember.
In short, a very good popular book.
I also recommandrai "Hyperspace" or "Paralleles universe" of the same author.
8/10