Like his elder brothers, Claude Sautet and Jean-Pierre Melville, Alain Corneau began to cut his teeth in French cinema with a series of fine thrillers: "la Menace" (1977) and "Série Noire" (1979) among others. "Police Python 357" is a good example of how Corneau conceived and shot his works at this time of his career. They had a splendid cinematography, painstaking screenplays and a sophisticated directing elaborated for efficiency's sake.
The police superintendent Ferrot (Yves Montand) is a cop with unconventional methods who usually works all alone. He makes the acquaintance of a young woman Sylvia Léopardi (Stefania Sandrelli) and becomes her lover while ignoring that she has another lover: his superior Ganay (François Périer). When the latter learns it, he kills her in a fit of anger. Ferrot has to investigate the murder and all the clues are inexorably against him...
One could deem that this kind of far-fetched story isn't exempt from glitches and sometimes, one can see right through it but Corneau's pedantic directorial style helps to conjure up a stifling, dusky atmosphere. The first part of the film before the night of the murder might seem uninteresting and however, it is crucial for what will follow this key-moment. Corneau falls back on a sober treatment with rather sparse moments and short appearances by secondary, minor characters whom the viewer will see again during the investigation. In spite of drawbacks, Corneau and his scenarist Daniel Boulanger penned a deft story. Ménard (Mathieu Carrière) who sometimes expresses his surprise because Ferrot keeps a relatively low profile during the investigation. But his superior knows that he usually works alone. Actually, Ferrot has to find solid tricks to muddy the waters and so to exonerate himself. Eventually, the chief idea of the film concerns Ferrot himself. He's a cop who bit by bit loses his identity and finds himself in the heart of a terrible depersonalization. It is epitomized by the moment when he throws himself acid on his face so that witnesses won't recognize him when he is brought face to face with them.
The backdrop of this thriller, Orléans is efficiently enhanced by Corneau's camera and helps to inspire this eerie thriller its pernicious charm.

If you want to see a movie about two utterly unsympathetic characters, this is the one. The acting is superb, both from John Cassavetes as the insane paranoid whom, as the saying goes, they REALLY ARE out to get, and from Peter Falk as his lifelong best friend to whom he turns for rescue. Big mistake, but since they're both amoral mobsters, and misogynistic bastards to boot, it's hard to decide whom to root for LESS. Only writer/director Elaine May could have gotten away with this one. I thought it interesting that in a lengthy interview with producer Michael Hausman included on the DVD, he disclosed that the two stars had "very different ideas" about the script, that the director was nearly impossible to work with, that the director of photography had impossible demands made of him, that the crew was constantly angry about being made to sit around waiting, and so on. This mood of one big VERY dysfunctional family comes across clearly on the screen.