Grégoire Lecomte, the unlucky actor anxious to find a "real job", goes to take a screen test for a role of a killer, but gets to mafiosi by mistake. He takes their don for a producer, and they mistake him for a hitman with whom they had an appointment. Deluded Lecomte signs contract with them. He is supposed to kill gun dealer Otto Krampe at his birthday party in Saint-Tropez by piercing him with a cap of the umbrella with a built-in syringe with potassium cyanide. Lecomte is not aware that it has to be a real murder.
Pierre Richard
Grégoire Lecomte, acteur à mi-temps, dragueur à plein temps
Valérie Mairesse
Sylvette, alias Bunny, inspecteur à la D.S.T.
Christine Murillo
Josyane Leblanc, contractuelle parisienne, régulière de Grégoire
Gérard Jugnot
Frédo, agent artistique de Grégoire
Gordon Mitchell
Moskovitz, le tueur à gages
Roger Carel
Salvatore Bozzoni, couturier et fournisseur de poison
Gert Fröbe
Otto Krampe, dit La Baleine
Maurice Risch
Le producteur de Paris