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.

For fun and to dazzle his wife, the novelist Morgan steals a ring and gets rid of it in the costume jewelry section of a supermarket. Sophie buys the diamond, which forces the novelist to embark on crazy adventures to recover the jewel.

The manager of a firm has a very unusual idea : asking his employees to pose as gangsters and to hold up a bank before returning the stolen money and pocketing the reward. But things do not go according to plan and the phony thieves get stolen in their turn. They have no other choice than turning into amateur detectives to be able to pay back the stolen dough.

The young Mathilde de Marsan, believes she is in love with a singer, Philippe Mazières, and steals his photo. This one, who had written a song start, searches for this photo as far as the castle of Geoffroy and Estelle de Marsan, where Mathilde's uncle and aunt take him for the husband of one of their guests, Claude Cartier. and will finally marry her while Georges, Claude's ex-fiancé will fall in love with his hosts' niece, Mathilde.

Jacques Montet, a successful crime story writer, has already written a hundred books and would like to call it quits now to devote himself to loftier writing. But his wife, a cold-hearted, money-minded, bossy woman won't allow. All the more as she is the one who supplies Jacques with the plots of his detective stories. When Jacques, yearning for true love, meets young, pretty Muriel, he can't stand the situation any longer. Fortunately - for him - the plot of the 101st detective story imagined by his wife is about a ... perfect crime. He simply has to follow her instructions to ... get rid of her. Everything goes according to plan until Jacques discovers a scary detail: the presence of a mysterious witness on the scene of the crime.

An accordionist playing in disreputable halls is mistaken for a gangster by a special envoy from the American crime syndicate in charge of investigating the French milieu. The American will prepare a hold-up with a gang of women specialized in scamming tourists. But the accordionist will make the hold-up fail and all the criminals will end up behind bars.

When Nathalie, a shoe seller, is abducted, her mother Flora wastes no time taking matters into her own hands. Reluctant to call in the police, she galvanizes her three other daughters into action.

Marie-Thérèse is firmly involved in a charity dedicated to the rehabilitation of prostitutes. She approaches Marcelle who, for the love of Pierre, an honest painter, hides her dishonorable profession, and she befriends Maria, in love with the gentle René. Marcelle's aunt is murdered, and her daughter arrested. Marie-Thérèse sets out to prove her innocence, but the two boys learn all about the two unfortunate women. Pierre is unforgiving. Happier, Maria will start a new life with René.

A singer tries to rescue a man drawn into the drug trade.

Barbara Van Looren is the lively, clever daughter of the well-known shipowner. For her, life is a breeze, even when she's kidnapped by Mike Cortez's men. A young journalist, Mercier, who tried to defend her and was forced to follow her, doesn't share her optimism and manages to escape. Barbara is sequestered because her father has caught wind of a diamond deal. If he renounces the customs action, his daughter will be returned to him. Mercier, with the help of a couple of loyal friends, discovers the instigator of the traffic, a member of the board of directors, and finds Barbara, still as petulant as ever.