Taking advantage of the shooting of a film ,gangsters stage a hold -up.A black man ,Selim ,is accused , whereas the leader of the gang is none other than Spoletti,who manages a music hall ,the star of which,Lily ,steals one of the brooches of the loot.Maurin,jealous of Lily, gives the jewel -he thinks is worthless- to Myriam ,Selim's fiancee, which puts all the blame of this innocent man.