Molly said:
I thought Chewbacca was renamed in France too?
Yup: Chico. But just for episode 4. To the general public in France, he's just known as Chewbacca.
The translators probably thought his name came from "Chew tobacco" which, in turn, is "chique du tabac". Chique -> Chico. Voilà.
There are a couple of weird translations like that in the French version of Episode 4 that they didn't use for the subsequent films.