Razzia sur la chnouf (1955)

Henri, the Man from Nantes, comes back to his country after a successful stay in the United States, where he was working for Liski, the drug dealer. With the fame of being a tough guy preceding him, he sets himself to the task of knowing why the French operations were not so profitable - and soon he is master of all links of the organization. He can now get it honed to perfection - or destroy it. Only… the Police is following his every step! Is Henri what he says he is, or an undercover detective from the French police?

IMDB

Storyline
Le redoutable Liski, chef du gang parisien de la drogue, engage Henri le Nantais pour remettre de l'ordre dans l'organisation du réseau. Le Nantais démonte donc minutieusement tout le mécanisme du trafic de la "chnouf". Sa mission accomplie, il peut dévoiler sa véritable identité d'inspecteur de police et mettre tout ce joli monde sous les verrous.