George Peppard
Reno Davis

Inger Stevens
Anne de Villemont

Orson Welles
Leschenhaut

Perrette Pradier
Jeanne-Marie

Keith Michell
Morillon

Geneviève Cluny
Veronique

Maxine Audley
Mathilde Rosier

Ralph Michael
Claude de Gonde

Barnaby Shaw
Paul

Jacques Roux
Maguy

Patience Collier
Goonelle

William Job
Bourdon

Ave Ninchi
Signora Orragi

Renzo Palmer
Monk

Peter Bayliss
Edmond Rosier

Francesco Mulè
Policeman at Trevi Fountain

Rosemary Dexter
Daniela

Raoul Delfosse
Louis Le Buc

James Mishler
Jesse Hardee

Jean Louis
Driot

Jean Hébey
Man in charge of sleeping cars

Jacques Stany
Georges - the family chauffeur

Paule Albert
Sophie

Calisto Calisti
Police Inspector at Rome Station (uncredited)

Andrea Esterhazy
de Villemont Party Guest (uncredited)