Burning Fuse(1957)

Original title: Le Feu aux poudres

Lola, the wife of arms dealer Pedro Wassewich, is attracted to Ludovic, a young painter who turns out to be the emissary of a notorious gangster. He claims to have been sent by the latter to pick up a shipment. In fact, it's the police who, behind the scenes, orchestrate the operation to catch Wassewich red-handed.