What is the French translation for 'Diagon Alley' from Harry Potter?

As Diagon is a the name, it will not change,

ruelle de diagon

http://www.linguee.fr/francais-portugais/traduction/la+ruelle.html

Diagon Alley, Chapter five of Harry Potter and the Philosopher's Stone is 'Le Chemin de Traverse', Harry Potter a l'ecole des sorciers.

I have both the English text (Ted Smart) and the French (Folio Junior). So the answer is Le Chemin de Traverse.

I've found it interesting to see what the "Harry Potter" translators decide to translate or alter and what they leave alone. The Italian for "diagon(al) all(e)y" would be "vicolo diagonale," but the name is left in English in the Italian edition.

However, several names are changed: Albus Dumbledore becomes Albus Silente; Snape is called Piton, presumably from "pitone" for "python." The note on the translation says that the translator sometimes decided to come up with new names that she felt both reflected the personalities of the characters and that Italian readers would grasp.

Chemin de Traverse is the translation!

http://harrypotter.wikia.com/wiki/List_of_locations_in_other_languages