In this light, sometimes tongue-in-cheek mystery based on a Charles Williams thriller -- with snippets of Hitchcock, Kubrick, and even Victor Hugo -- director François Truffaut showcases one of his favorite actresses, Fanny Ardant, as an enterprising secretary in love with her boss but up against clearing him of murder.
Julien Vercel (Jean-Louis Trintignant) is a real estate dealer accused of killing his wife and her lover.
He hides in his office while his secretary, Barbara (Ardant), sets out to discover what really happened and why. When Barbara starts looking into the dark past of her boss' wife, she comes across illicit love affairs, a prostitution ring, and shady private detectives, until, finally, her suspicions turn toward Julien's lawyer himself.
Tragically, Vivement Dimanche was to be Truffaut's last film; the great French director died of a cancerous brain tumor in 1984.