The unusual beginning of the movie offers some insight into why “Severine” (Catherine Deneuve) feels unfulfilled in her marriage to her attractive but passionless husband, "Pierre" (Jean Sorel). It’s revealed that they haven’t even slept together yet! Growing increasingly frustrated, she learns about a place run by "Madame Anais" (Geneviève Page), where these issues could potentially be resolved. Though initially hesitant, she begins to form numerous new connections as her daytime activities begin to compensate for what's missing in her marriage with the unsuspecting "Pierre." The situation becomes more complicated when she meets the rather mysterious young “Marcel” (Pierre Clémenti). He notably has a set of metal teeth – and his frequent visits lead him to develop an attachment to her. She attempts to create some space between them, but after he discovers her home, events take a darker turn. Deneuve is excellent portraying the sophisticated woman involved in prostitution with unusual desires, as is Page playing the wise and professional owner. The film’s success lies largely in Buñuel's intelligent adaptation of Joseph Kessel’s original story, which allows Deneuve to portray “Severine” as an engaging, if not always sympathetic, character—one who embodies loyalty, independence, and genuine inner conflict while embracing her erotic explorations and ultimately managing two very different lives with growing skill. The film possesses a richness – without relying on traditional historical settings – and the music enhances this compelling narrative about a woman's quest for satisfaction and enjoyment!

Source on TMDB