This fast-paced mystery is in part based on a novel by Yves Ellena and is at least equally based on the 1943 classic Le Corbeau, which in 1951 was produced in English by Otto Preminger as The Thirteenth Letter. In this movie, someone is using a pirate radio broadcast to dish the dirt on the lives of the elite of a small French town.

Claude Brasseuras Paul Maurier, le correspondant du journal local
Pierre Arditias Duval, l'inspecteur
Christine Boissonas Agnès Deluca
Évelyne Bouixas Françoise, la compagne de Duval
Jean-Pierre Bissonas Le commissaire Bouthier
Roger Planchonas M. Faber, le maire
Édith Scobas Mme Michel, la libraire
Jean-Claude Dreyfusas Rosati, le boucher
Bernard Blochas Gerfaut, l'entrepreneur
Yves Afonsoas Roustan