Paul (Daniel Auteuil) is a respected, successful surgeon married to the devoted Lucie (Kristin Scott-Thomas). They live in a beautiful house, want for nothing and seem perfectly happy but beneath the calm surface of their marriage lurks all kinds of niggling resentment and unspoken discontent. Daniel Auteuil has the meatier role and is good at conveying the grumpiness of advancing age.
He retains our sympathy as he meets a younger woman Lou (Leila Bekhti) who claims that he once operated on her. Initially, she seems like a stalker and the film could be straying towards Fatal Attraction territory but then it is Paul who becomes obsessed by her as he recklessly risks his perfect life. Before The Winter Chill often feels more of a melancholy character study than a thriller. When it delivers on that intrigue with a completely unexpected denouement, you realise it has been cleverly structured and perfectly executed.