Henri Faust, retiring after 50 years as a professor in a circa-1700 French university, despairs at the ravages of old age ... whereupon Mephistopheles, agent of Lucifer, appears as a virile, handsome young man and exchanges bodies with him to induce Faust to sign a pact to exchange his soul for renewed youth, riches and power. But though the "new" Faust is attracted by the material improvements in his life, he remains wary of signing, while Mephistopheles, now posing as the aged professor whose body he inhabits, must find a way to trick him into signing the pact - and dissuade him from the love of a gypsy girl who prays for his soul - or find himself damned by his own Master...

Michel Simon
as Mephistopheles / Old Prof. Henri Faust

Gérard Philipe
as Young Henri Faust / Young-Looking Mephistopheles

Nicole Besnard
as Marguerite the Gypsy Girl

Simone Valère
as The Princess

Carlo Ninchi
as The Prince

Raymond Cordy
as Antoine the Servant

Paolo Stoppa
as Official

Tullio Carminati
as The Diplomat

Gaston Modot
as Gypsy