The Madman of Lab Four

Jean Lefebvre

Eugène Ballanchon, scientific researcher, single

Maria Latour

Régine, Mr. Beauchard's spy

Bernard Blier

Mr. Beauchard, executive secretary linked to a gang

Michel Serrault

Mr. Granger, director of the scientific laboratory

Pierre Tornade

DST inspector

Pierre Brasseur

Father Ballanchon

Margo Lion

Mrs. Ballanchon, Eugène's mother

Robert Dalban

Merchant, spy in the laboratory

Mario David

Mario

Henri Virlogeux

Scholar

André Chaumeau

Baron

Jean Franval

DST inspector

Paul Préboist

Agent

Alain Janey

Fred

Sabine Sun

Baroness

Yvon Sarray

Pedestrian

Max Arian

Extra worker (uncredited)

André Cagnard

Jo (uncredited)

Guy Delorme

Actor from the western (uncredited)

Marius Gaidon

Police officer (uncredited)

Henri Guégan

Actor from the western (uncredited)

Jean Ozenne

Minister (uncredited)

Laure Paillette

Traveler (uncredited)

Lionel Vitrant

Actor from the western (uncredited)