Daniel Auteuil stars as the infamous Marquis de Sade, who at the beginning of Sade, is serving a sentence in Paris' grim Saint Lazarde prison. The year is 1794, and Sade is being persecuted for his steadfast atheism, which runs counter to the beliefs of Robespierre, France's terrifying revolutionary leader. The Marquis is granted something of a reprieve when he is transferred -- courtesy of his mistress Sensible (Marianne Denicourt) -- to Picpus, a former convent that now serves as the equivalent of a luxury prison. Although Picpus is not without its own guillotine and mass grave, Sade is more concerned with the blossoming Emilie (Isild Le Besco). Meanwhile, Sensible, who has a son who calls Sade "Papa," is forced to share the bed of her own protector, Fournier (Gregoire Colin), a moody lout who hates Sade and works for none other than Robespierre.