Narcisse is a doorman for a jeweler but dreams of becoming a private detective. The Criminas agency hires him and he comes to the aid of his former boss's nephew, accused of stealing jewelry. He first passes for the accomplice of the young man but soon discovers the culprit.

Bach
Narcisse

Paul Bernard
André
Monique Bert
Mag
Ginette Gaubert
Olga Worskaïa

Louis Florencie
Baudry

Armand Lurville
Lesueur

Jacques Dumesnil
Stefani

Ginette Leclerc
Zita

Georges Prieur
Durandel

Georges Morton
Olive

Edmond Castel
Mr. Estrade
Simone d'Arche
Dora

Jules Moy
The loan shark

Alexandre Mihalesco
The extra
Andrée Champeaux
The baron's friend