On instructions of the French company Pathé Frères, Alfred Machin develops a film industry in the Netherlands and Belgium from 1912 to the advent of World War One. He directs several quality films including La Fille de Delft, Maudite soit la Guerre and this wonderful gem Le Diamant Noir. A man is accused of theft and decides to quit the country. Machin's favourite pet, the panther Mimir shares the lead roll in this film with a magpie.

A mine owner discovers a vein of gold but unfortunately dies. His wife doesn't want to sell the mine and so the forman decides to lock her up in a cottage with a dangerous and hungry leopard.