Robert Lamoureux

Arsène Lupin / Lieutenant André Laroche

Robert Dalban

Inspector Béchoux of the Judicial Police

Alida Valli

Aurélia Valéano

Jacques Dufilho

Albert, manservant

Yves Robert

La Ballu

Roger Dumas

Isidore Bautrelet aka 'Véritaz'

Hubert de Lapparent

French Consul in Florence

Jean Bellanger

Sleeping car employee

Liliane Chenevière

Michel Etcheverry

Van Nelden, collector