Géo Paquet, aka The Gorilla, breaks from jail. Now an escaped convict, the elite agent must infiltrate a dangerous gang working for a foreign embassy as their leader, a spy enjoying diplomatic immunity, can't be arrested by regular police.

Lino Ventura
as Géo Paquet, Le Gorille

Charles Vanel
as Colonel Berthomieu

Pierre Dux
as Veslot

Bella Darvi
as Isolène

René Lefèvre
as Commissioner Blavet

Robert Manuel
as Casa

André Valmy
as Mauricet

Henri Crémieux
as X.A. Pallos

Jean-Roger Caussimon
as Léon

Jean-Max
as Councilor Smolen