My only complaint about this film is that the anti-hero, Henri Landru, is played by George Sanders. Now Sanders was a fine actor...but with his melodious British accent, he seemed oddly out of place because his character was supposed to be French...and everyone else in the film has a French accent! Still, considering all I liked, I can live with this.
When the story begins, Henri meets a very mercenary woman (Corinne Calvet) and she sweet-talks a lot of money out of him. But he's not a wealthy man and cannot afford such a 'lady' and instead of just dumping her, he goes on a killing spree in order to become a rich man and to be able to afford her! So, again and again, he finds widows and manages to trick them out of their money and he kills them...and in a few cases brutally so. What's next? See the film.
Henri Landru could have been a pathetic and thoroughly stupid character...and that would have harmed the film. Fortunately, while he is at first an old fool, he doesn't stay stupid forever and his cleverness and persistence make the story interesting...as were some of the murders...which were amazingly grisly for the time. Well worth seeing and an exciting tale.