A well-known business lawyer is shot dead in the courthouse. A commissioner of the Criminal Brigade is in charge of the investigation and is helped by a journalist.

Claude Brasseuras Commissaire Martin Griffon
Gabrielle Lazureas Sybille Berger
Jean-Claude Brialyas Le contrôleur Jean-François Rambert
Jean-Louis Trintignantas Christian Lacassagne
Dayle Haddonas Suzy Thomson, alias D'Annunzio
Robert Hirschas Avram Kazavian
Jacques Dacqmineas Me Antoine d'Alins
Luc-Antoine Diquéroas Antoine Gomez
Yves Beneytonas Millard, le directeur du ministre de l'Intérieur
Pierre-William Glenn