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.
Jean Lefebvre
as Eugène Ballanchon, scientific researcher, single
Maria Latour
as Régine, Mr. Beauchard's spy
Bernard Blier
as Mr. Beauchard, executive secretary linked to a gang
Michel Serrault
as Mr. Granger, director of the scientific laboratory
Pierre Tornade
as DST inspector
Pierre Brasseur
as Father Ballanchon
Margo Lion
as Mrs. Ballanchon, Eugène's mother
Robert Dalban
as Merchant, spy in the laboratory
Mario David
as Mario
Henri Virlogeux
as Scholar
André Chaumeau
as Baron
Jean Franval
as DST inspector
