Sophia Loren as Lady Louise Lendale / Lady L

Paul Newman as Armand Denis

David Niven as Dicky, Lord Lendale

Peter Ustinov as Prince Otto of Bavaria

Marcel Dalio as Sapper

Michel Piccoli as Lecoeur

Claude Dauphin as Inspector Mercier

Cecil Parker as Sir Percy

Philippe Noiret as Ambroise Gérôme

Jacques Dufilho as Bealu

Eugene Deckers as Koenigstein

Daniel Emilfork as Kobeleff

Hella Petri as Madam

Jean Wiener as Krajewski

Roger Trapp as Police Inspector Dubaron

Jean Rupert as

Joe Dassin as Police inspector

Jacques Legras as Police inspector

Mario Feliciani as Italian anarchist

Sacha Pitoëff as Bomb-throwing revolutionary

Arthur Howard as Butler

Dorothy Reynolds as

Jacques Ciron as

Hazel Hughes as

Tanya Lopert as Agneau (uncredited)