In Belle Époque Paris, Marie, Simone Signoret, a striking woman of the demimonde known for her golden hair, becomes entangled with Roland, a brutish criminal in a local syndicate led by Félix Leca Claude Dauphin. At a riverside tavern in Joinville, after a bank robbery, Marie is introduced to the handsome carpenter Georges Manda by his old friend, Raymond Bussières — a gang member who had bonded with Manda years earlier when they shared time in prison. Marie is instantly drawn to Manda, and after a quiet dance, Roland attempts to bully him, only for Manda to knock Roland out with a single punch.
Roland’s jealousy deepens, but Marie has learned since returning to Paris that Manda has a fiancée, and she tries to forget him. Yet Manda appears at the gang’s regular bar, L’Ange Gabriel, to take Marie from Roland, and the men retreat to the back for a fight. Leca, who wants Marie for himself and is weighing whether she will “buy” herself from Roland, sets the ground rules for the confrontation. He places a knife on the ground between Manda and Roland; Manda seizes control of the knife and fatally stabs Roland. His fighting prowess impresses Leca, who offers Manda a place in the gang, but Manda declines. Marie, witnessing Roland’s body, leaves the scene alone.
Anatole, a waiter at L’Ange Gabriel, had spotted trouble brewing and alerted the police, who arrive as the gang attempts to dispose of Roland’s body. Anatole is then found dead, killed on Leca’s orders for calling the police, yet the death is staged to look like an accident, and Leca even urges the gang to contribute to Anatole’s funeral.
Manda quits his job and plans to flee town when a note from Marie brings him back. They meet in Joinville and live for a time on a small farm, enjoying a fragile idyll. Meanwhile, Leca uses his corrupt police connections to frame Raymond for Roland’s murder, and then surprises the lovers with a visit to say that Manda is safe because Raymond has been arrested, hoping Manda will emerge from hiding to rescue his friend and, in the process, win Marie. True enough, Marie awakens to find that Manda has gone to surrender himself.
Manda signs a confession, but Raymond remains in custody. While the frustrated inspector tells him he is charged as an accessory to Roland’s murder, Raymond glimpses Leca’s name on a note, revealing his boss’s duplicity, and he passes this information to Manda during transport to La Santé Prison.
Leca refuses to interfere with the transport to free Manda and Raymond, so Marie hires a coach and orchestrates the escape herself, though Raymond is shot in the process. Manda drops him off at L’Ange Gabriel to die among his friends and then hunts down Leca, finding Marie’s slippers in Leca’s bedroom. He eventually spots Leca in the street and chases him to the police station, where, before the astonished officers, he grabs a pistol, pursues Leca into a small courtyard, and empties the gun into him. Now deprived of work, friendship, and love, Manda surrenders to the police.
Paul, a member of Leca’s gang, takes Marie to a hotel room overlooking the site where Manda’s execution is to take place. He falls asleep, but at dawn Marie witnesses with horror as Manda is led to the guillotine and beheaded. She droops her head in sorrow, and the final image returns to the two dancing together in the Joinville tavern, now alone on the dance floor.
