As a recovering French Lit student, I've come across quite a few French names that send me rushing to the Internet - "Guillaume is related to William? Of course!" Some names seem to defy modern or Anglicized translations, though, and many of those I've found in medieval French texts.
Chrétien de Troyes, Marie de France, Jean Bodel and Christine de Pisan are just some of the authors I've drawn from to make this list. Some names are not uncommon, while others seem totally unique. And quite a few can be found in the Tales of King Arthur!
What are some of your favorite French names, old and new?
Online sources: Old French Literature, Medieval French Literature, History of French Literature