James Garner as Casey Barnett

Dick Van Dyke as Paul Sloane

Elke Sommer as Nikki Dunnay

Angie Dickinson as Laurie Gibson

Ethel Merman as Madame Coco La Fontaine

Carl Reiner as Rodin

Pierre Olaf as Inspector Carnot

Miiko Taka as Chou Chou

Roger C. Carmel as Zorgus

Irving Jacobson as Mr. Fromkis

Jay Novello as Janitor

Naomi Stevens as Mrs. Sarah Fromkis

Renzo Cesana as Pepe de Winter

Leon Belasco as Prince

Louis Mercier as Magistrate

Maurice Marsac as Prosecutor

Fifi D'Orsay as Fanny

Marcel Hillaire as Executioner

Dawn Villere as Couchette

Nan Martin as Margo

Victoria Carroll as Yvette

Sharon Shore as Betti

Astrid De Brea as Cerise

Émile Genest as Cesar (uncredited)

Brad Johnson as Art Collector (uncredited)

Charles Sherlock as Courtroom Spectator (uncredited)

Hal Taggart as Tourist (uncredited)