As a Frenchman, I think I would have to pick Victor Hugo. He occupies the place of the ultimate milestone, the final boss of all of french literature. His work is so diverse, so monumental, considered so flawless that his figure is almost crushing in the french literary world. He is so reinforced in our culture than it is almost kind of scary to read him. I remember reading one of his poems, and having to take breaks between pages because of how strong it was in style.
Our literary heritage is very large, and there are so many incredible french writers, past and present, but if we had to take one out to fight in the World Battle Royale of Literature, it would have to be him.