Doesn't have the charisma to play it. Hell, save for the fact he's got a natural accent(which doesn't sound cajun tho) he's a horrible choice.

Imho, Brad Pitt circa fightclub would make a good gambit as far as attitude/looks go(since gambit had that scruffy whiteguy look in the comics). Its just I can't imagine him with a french accent(although he did pull off that cockney accent in snatch)