Arsène Lupin / Lieutenant André Laroche

Robert Lamoureux

Inspector Béchoux of the Judicial Police

Robert Dalban

Aurélia Valéano

Alida Valli

La Ballu

Yves Robert

Isidore Bautrelet aka 'Véritaz'

Roger Dumas

Albert, manservant

Jacques Dufilho

French Consul in Florence

Hubert de Lapparent

Sleeping car employee

Jean Bellanger

Van Nelden, collector

Michel Etcheverry

General

Jean Galland

Madame du Bois-Lambert

Gisèle Grandpré

Henri

Harold Kay

Attaché of the French consulate in Florence

Paul Müller

Agnès, nurse

Ginette Pigeon

Sidekick

Gérard Darrieu

Michel Vocoret

(uncredited)

Pierre Duncan

SNCF employee (uncredited)

Gabriel Gobin

Prison guard (uncredited)

René Hell

(uncredited)

René Lefèvre-Bel

(uncredited)

Judith Magre

(uncredited)

Claude Mercutio

Drunkard of Enghien (uncredited)

Paul Préboist

Traveler on the train (uncredited)

Robert Rollis

Secretary of the archives (uncredited)

Paul Villé