Paul Dorgères, a wealthy industrialist, has been mysteriously murdered. The investigation is entrusted to the experienced Chief Inspector Bonnardel and his young rookie assistant, Inspector Richard. Suspicion turns to his mistress Catherine Villard, with whom he had just broken up on the night of the crime. She is soon arrested and charged. However, Inspector Richard discovers a button at the scene of the crime which could help him to trace the trail and confound the culprit(s).
as L'inspecteur-chef Bonnardel
as L'inspecteur Richard, jeune assistant débutant de Bonnardel
as Catherine Villard, maîtresse de Dorgères
as M. Phalempeau, homme d'affaires
as L'inspecteur Sylvestre, adjoint de Bonnardel
as Maître Landry, avocat pénaliste, ténor du barreau
as Mme Le Mesles
as Le médecin légiste
as La détenue-manucure
as Le juge d'instruction Ferrand
as Paul Dorgères, homme d’affaires
as Étiennette, la concierge
as Le concierge
as Pierre
as Le détective Henri Bouteiller
as Le commissaire
as Bertrand Moal
as Le tailleur
as Le maître d'hôtel de Dorgères
as L'hôtelier de Marseille
as La cuisinière de Dorgères
as La voisine
as La nièce
as La vendeuse d'articles de maroquinerie
as Une femme
as Le vendeur de boutons (uncredited)
as (uncredited)
as Le Mesles (uncredited)
as Un journaliste (uncredited)
as Amélie, la soubrette (uncredited)
as Un homme (uncredited)
