How can you say French literature is so good?

I do not personally feel that French literature is better than any other type of literature. If you compare the style and impact of authors such as J. B. Priestly, Aldous Huxley, and George Orwell and countless other English/American authors with the style and impact of French literature, you will likely find many similarities.

There is good French literature as much as bad, just as there is good English/American literature as there is bad. Some people claim that the intent of French literature is somehow purer than other literature, but that is only their opinion. I suggest reading some of the popular French literature as well as English/American literature and decide for yourself.