A tricksy narrative that keeps the viewer guessing until the very end.
On one level this is a good old fashioned mystery story, and on another it is a parable for the breakdown of trust in a community (a very relevant concern in France during WW2).
It is always refreshing to see how far French cinema was in advance of the USA and the UK throughout the 1930s, 1940s and 1950s. French directors were not afraid to make movies for grown-ups, with a frankness about sex that makes most British and American films of the period look childish.
Controversial pre-noir made in France during the occupation based on a real life scandal from the early '20s. A doctor in a provincial town is accused via anonymous letters of carrying out illegal abortions and having affairs with married women. Soon all the residents are persecuted by a barrage of poison pen correspondence.
The film aroused antagonism all across the political spectrum. Most obviously it reflects the collaboration with the enemy; the public who anonymously denounced their neighbours to the Gestapo. Oddly the Nazis didn't stop the release, maybe because it was bad for French morale with its negative critique of national spirit.
The film itself was a provocation, like the poison pen letters. Postwar, it was banned by someone or other for years. Henri-Georges Clouzot creates that shadowy pessimism which came to be associated with film noir; the big final twist is his signature. He got called the French Hitchcock though this hasn't quite the suspense that implies.
It's best as an allegory for France under the occupation and a showcase for some piquant ensemble acting, led by Pierre Fresnay as the doctor. There's a resonant impression of small town life where everyone knows everyone else's business, but has something of themselves to hide. Have to wonder though if Clouzot ever saw the '39 British thriller, Poison Pen...