Jean Gabin stars as Vallois, a vice inspector for the Paris police. Vallois takes special interest in the plight of drug-addicted Lucky (Najda Tiller), whom he considers to be more victim than criminal. Taking it upon himself to wean Lucky away from narcotics, Vallois also wins her love -- and, incidentally, smashes the dope ring responsible for her addiction. Second-billed Danielle Darrieux actually has a minor role, which she pulls off with finesse.

Source : allmovie.com