Paul Meurisse

as Stanilas Octave Seminario aka 'SOS', détective

Micheline Francey

as Muriel Pescara, the daughter

Gilbert Gil

as Charles Pescara, the son

Pierre Renoir

as Doctor Gérard Pescara, the father

Jean Tissier

as Guillaume

Pierre-Louis

as Paul Wantz

Junie Astor

as Hélène Tassin, nurse

Jean Debucourt

as Doctor Vermeulen

Jean Brochard

as Investigating judge

Mady Berry

as Brigitte Tassin

Pierre Palau

as Doorman

Arthur Devère

as Lock keeper

Marcel Pérès

as Road mender

Sinoël

as Gardener

Georges Bever

as Baptiste, clerk

Madeleine Suffel

as Hotel boss

Michel Seldow

as Illusionist Pablo

Marc Arian

as (uncredited)

Léon Arvel

as (uncredited)

Alfred Baillou

as Man (uncredited)

Rivers Cadet

as (uncredited)

Marcel Charvey

as (uncredited)

Raymond Destac

as (uncredited)

Pierre Duncan

as (uncredited)

Cécile Eddy

as (uncredited)

Henry Gerrar

as Concierge (uncredited)

Claire Gérard

as Concierge (uncredited)

Colette Mareuil

as (uncredited)

Pierre Moncorbier

as (uncredited)

Geneviève Morel

as Pescara cook (uncredited)

Henri Niel

as (uncredited)

Julienne Paroli

as Gossip (uncredited)

Marcelle Rexiane

as Director (uncredited)

Maurice Salabert

as (uncredited)

Germaine Stainval

as Gossip (uncredited)

Jean-Marc Tennberg

as Agent on duty (uncredited)

Georgette Tissier

as Telephone operator (uncredited)