Bob is a gambler who lives on his own in the Montmartre district of Paris, where he is well-liked by the demi-monde community. A former bank robber and convict, he has mostly kept out of trouble for the past 20 years, and is even friends with a police commissioner, Ledru, whose life he once saved. Ever the gentleman, Bob lets Anne, an attractive young drifter, stay in his apartment in order to keep her from the attentions of Marc, a pimp he hates, and, after he discovers her asleep in bed with his young protégé Paolo, does not pursue Anne romantically, even though she remains flirtatious.