Remake of a 1959 movie of the same name by Julien Duvivier, based on a 1948 novel by Jacques Robert.
Subject: Marie-Hélène Dumoulin was a member of the Resistance network Vaillance; her code name was Marie-Octobre. The legendary Castille, leader of the group was killed by the Germans in somewhat unclear circumstances. 13 years after the war Dumoulin receives a hint that Castille was betrayed by a member of the network. She invites all 9 surviving members to a dinner, in which she plans to uncover the traitor.
Inevitably, this brings to mind an Agatha Christie movie where all the suspects are assembled in one place, each one's involvement in the crime sought by clever questioning and cross-questioning. However, there is something more here. In the course of the meeting we learn something about the Resistance; how its members came from all places in the political spectrum, the conflict between duty and personal feelings, the cruel but necessary decisions, the feeling of having been betrayed by the postwar government, the occasional support from outsiders (one of the anecdotes involving a policeman ignoring a radio is a scene in Jean-Pierre Melville L'Armée des Ombres, 1969). There was at least another spawn of the original movie, The Accursed (1957) where neither Duvivier nor Robert get credit.
Filmed theater? Perhaps, but alleviated with flashbacks and of the best quality. Nathalie Baye shows her usual excellence as Marie-Helene and the rest of cast plays at the same high level. Worth a watch.