After the failure of his recent criminal exploits, international con artist Alexandre Dupré sets off for Venice to try to dupe some Japanese business men into buying a fake copy of a stolen Caneletto. On the aeroplane, a stranger asks him to look after his briefcase until after they have landed. Alexandre agrees, but the stranger is shot dead soon after and Alexandre himself becomes the target of enemy agents who are keen to recover the briefcase...
L'Alpagueur is a free-lance spy from the French secret agency. He's put on the investigation about L'epervier, a serial-killer who employs young boys to help him robbing banks before killing them.
A serial-killer frightens Paris by phoning young ladies at night, telling them insults about their lives. Minos, as he calls himself, wants to prevent the world from free women and he targets at first these ones. Commissaire Letellier is given the investigation and he has hard work with the maniac.
This talkative and unevenly paced feature finds Fou (Jean Lefebvre) the inventor of a gas that makes the users fall in love. He is chased by his boss, the police, and spies, who seek to secure the secret recipe for their own selfish purposes. A shadowy American underworld figure tries to intimidate the inventor. A half-hearted attempt at comedy tries to go along with the double dealing and trickery of the thin plot of the film.