The film is a 125-minute, black-and-white biography of French priest and diplomat Charles Maurice de Talleyrand-Périgord (1754–1838), who served for 50 years under five different French regimes: the Absolute Monarchy, the Revolution, the Consulate, the Empire, and the Constitutional Monarchy. Its title comes from one of the main historical nicknames for Talleyrand, that he shares with demon king Asmodeus and English poet Lord Byron.
Married French lawyer Andre defends succesfully the case of Yvette, who committed a robbery. He falls in love with her, but she isn't true to him.
Ursula finishes her studies and returns to her aunt Florentine and uncle, Ribera who is the count. She falls in love with Lambert, the killer of her uncle.
Cute Sophie is an amoral French girl living in a sumptuous Venetian palazzo. She is the kept woman of a very rich but undesirable fellow named Eric von Bergen, an ex-nazi turned forger.
Léon Ménard, the village verger, is a decent young man whose hobby is to play the accordion. One day he is fired for having accompanied Mary Pinson, a singer deemed scandalous by the right-minded parishioners. Blinded by his love for Mary, Léon follows her to Paris where he becomes her plaything. With Mary's complicity, a gang of swindlers make him the puppet proprietor of a night club. But Léon can't live in a fool's paradise forever and soon finds himself on the street, forsaken and desperate. Luckily, the manager of a circus notices him while he is busking and he hires Léon at once. Not only will success come to him but he will win the love of sweet Solange.
With no contract in view, Aimé Barelli, the leader of the band of the same name, decides to take a holiday. As this is the Holy Year, the young artist accepts to follow his mother on a pilgrimage to Rome. His band members - complete with their agent - decide to follow suit. Good idea because on the train to Rome, there is a whole class of charming schoolgirls, including charming Rosita and - surprise ! - Nicole, Aimé's pretty but elusive beloved. The trip is cheerful but eventful and life gets even more complicated with the interference of Duranval, a fake talent agent but genuine trouble shooter. At a time confusion is such that a bomb explodes and the whole gang find themselves in ... heaven! But Saint Peter has pity on them and sends them back to earth. At long last Aimé can marry Nicole while his musicians spread mirth around them.
Maitre de Latour Martin had been reported missing during the war. Peace returned, he finds his two wives. Guilty of bigamy, he shelters the ladies in his home and a third woman arrives whom a dowry hunter had married thanks to the papers lost by the lawyer. Life at four is stormy and Maitre Latour regrets his life as a soldier.
