Alain Delon as Mr. Robert Klein

Jeanne Moreau as Florence

Francine Bergé as Nicole

Juliet Berto as Jeanine, Robert's mistress

Jean Bouise as Seller of the painting

Suzanne Flon as Concierge of rue des Abbesses

Massimo Girotti as Charles, Florence's husband

Michael Lonsdale as Pierre

Michel Aumont as Jew Affairs Section Official

Roland Bertin as Newspaper Director

Jean Champion as Morgue keeper

Etienne Chicot as Policeman

Magali Clément as Lola

Gérard Jugnot as Photographer

Hermine Karagheuz as Young Worker

Jacques Maury as Professor Montandon

Fred Personne as Police Commissioner

Francine Racette as Françoise / Cathy / Isabelle

Isabelle Sadoyan as Examined Woman

Louis Seigner as Mr. Klein's Father

Elisabeth Kaza as

Carole Achache as

Lucienne Le Marchand as

Rosine Rochette as

Maurice Vallier as

Pierre Vernier as Policeman

François Viaur as

Joseph Losey as Man at the Vel d'Hiv (uncredited)

Brigitte Ariel as (uncredited)

Marius Balbinot as (uncredited)

Maurice Baquet as Musician (uncredited)

Philippe Brizard as (uncredited)

Jenny Clève as (uncredited)

Raymond Danon as (uncredited)

Christian de Tillière as Auctioneer (uncredited)

Michel Delahaye as (uncredited)

Bernard-Pierre Donnadieu as Extra (uncredited)

Pierre Frag as Georges, Newspaper Seller (uncredited)

Mireille Franchino as (uncredited)

David Gabison as Bellboy (uncredited)

Maurice Jany as Driver in Ivry-la-Bataille (uncredited)

Stephane Quatrehomme as Pierre's Son (uncredited)

Jean Topart as Speaker's voice (voice) (uncredited)

Danielle Verne as Deportee (uncredited)

Dany Kogan as Michelle

Thierry de Brem as (uncredited)

Tina Aumont as Spectator (uncredited)

Nathalie Rigaux as Little girl at the Vel d'Hiv (uncredited)