France in the 1920s, and renowned lawyer Georges Sarret (Michel Piccoli) has just been awarded the Legion of Honour for his efforts, another medal to be pinned to his chest, but he is actually not worthy of any awards, for he has a dark side to his nature. He has become involved with the two German Schmidt sisters, Philomena (Romy Schneider) and Catherine (Mascha Gonska), who wish to be French citizens, something Sarret can help them with. Under his guidance, all they need to do is marry elderly Frenchmen, persuade them to take out life insurance, and wait till their spouses pop their clogs to collect the profits...
The story of Georges Sarret was a sensation in France of the early nineteen-thirties thanks to his singleminded pursuit of wealth, and the manner in which he went about acquiring it. When you know he was named The French Acid Bath Murderer by the press, you can understand what he was infamous for, but for this film version of his story and that of his two lady cohorts there were a few tweaks made to the events so that director Francis Girod could create one of those French movies which took a withering look at the bourgeoisie, much in fashion since the sixties and the dawn of the Nouvelle Vague.
But that wasn't what bothered audience of the day, nope, what put their noses out of joint was the fact that one of the actresses playing a greed-crazed killer was Romy Schneider. For millions she would always be identified with her quaint Princess Sissi role which had gained her stardom and a loyal following, so when she opted to spread her wings and take on a more sinister part, those fans felt it was a step too far and Le Trio Infernal was widely reviled. Such were the perils of being too close in the public's minds to a persona they saw as pure and unsullied, no matter that she had played in a variety of films since her breakout.
Still, the Philomena character was a fairly nasty piece of work no matter that she could be viewed as under the influence of the wicked Sarret, so you could acknowledge this was a jarring experience for the actress's adherents. But it was the section in the middle where Girod took his efforts into outright horror territory that were most upsetting for the day's audiences: he wasn't simply going to allow a gunshot or two to be heard then cut to the next day when Sarret organises the deaths of a wealthy couple in their mansion home, nope, he was going to show the murders and their aftermath in pitiless and disgusting detail. Thus if you ever wanted to know how to dispose of a body, there were many pointers here.
What Sarret does after he has gunned down the couple is drag them to the bathroom, strip then bundle them into the tubs and pour sulphuric acid over their corpses and wait for them to dissolve. As if that were not queasy enough, there's a lengthy sequence where later on he scoops the liquid remains out of the baths and into metal pails, which the sisters then empty into a hole in the garden. That was their downfall in real life because the stench this created was enough to alert the authorities that something was up, but Girod went on, giving a decadent take on their next scheme where they exploit a young tubercular woman who ends up as Catherine's lesbian lover and eventual tragedy ensues, though how upset you are depends on how you feel about the corrupt threesome after spending over an hour and a half in their vile company. Though a comedy, you needed a strong or extremely right-on sense of humour to find much amusing; the leads impressed, however, and Ennio Morricone's score was willfully eccentric.