This is actually rather a good, but not particularly noteworthy, detective movie. Chabrol re-uses a character of an earlier film, Inspecteur Lavardin from Poulet au Vinaigre, which was probably the most successful ingredient of that film. This later film is more entertaining and accessible than Poulet, primarily because it benefits from having a much better script, with more than a smattering of humour. In addition, the main characters are better drawn and acted than in Poulet. Of particular note are Jean-Claude Brialy playing Lavardin's outrageously camp and eccentric host, and Jean Poiret, now comfortably installed in the role of the unconventional, if not to say dangerous, detective Lavardin.
The plot is quite sophisticated, with some clever twists and turns. The unmasking of the murderer and the transfer of guilt are quite cleverly engineered, although the conclusion does raise some questions about Lavardin's (and Chabrol's?) own personal morality. That, coupled with Lavardin's somewhat brutal technique from extracting truth from the witnesses and suspects, can only serve to undermine his position as the good guy in any subsequent film.
The plot is quite sophisticated, with some clever twists and turns. The unmasking of the murderer and the transfer of guilt are quite cleverly engineered, although the conclusion does raise some questions about Lavardin's (and Chabrol's?) own personal morality. That, coupled with Lavardin's somewhat brutal technique from extracting truth from the witnesses and suspects, can only serve to undermine his position as the good guy in any subsequent film.