Max is a detective in Paris who is aloof, independently wealthy, and frustrated by gangs of criminals he is unable to apprehend. He decides to get a group of small-time criminals to rob a bank, led by an old acquaintance, in order to restore his reputation and preserve his face. Max receives intelligence from a reluctant captain, and he begins spending evenings with Lilly, a prostitute who is the girlfriend of the group's leader. He urges Lilly to consider her future by pretending to be a wealthy banker with unlimited resources. A payroll that goes through his bank is alluded to by him. The plan is effective, the small-time burglars believe they are prepared to make a large gain, and the police are present. What could possibly go wrong with Max's icy scheme? Who has been caught?