Psychonauts have one of the best French voice acting I know, but some of the accents can be rough I think.

Neverwinter Nights 2 has good french dubbing. Not stellar, especially regarding secondary NPC, but above the usual quality of french dubbing. It's one of the very few games I enjoyed more in french than english (the other being The Witcher 2, but you'll need a decent rig for that one).