In August 1895, he partnered with the astronomer Joseph Vallot, the famous engineer Gustave Eiffel, and the financier Alfred Besnier to make the purchase.

Louis Feuillade (Judex, Les Vampires, Fantômas) was to follow as the Studio Director when Guy left for Fort, Lee, New Jersey in 1912, where she subsequently opened her own production company—Solax Studios— and it was then that Gaumont rapidly expanded the business into cinematographic equipment for amateurs.

As one of the two dominant forces in film in all of Europe (the other being Charles Pathé), World War I profoundly affected Leon Gaumont's business fortunes.

Upon his retirement to Provence, a restructuring of corporate ownership took place through financing provided by the Banque Nationale de Crédit and with a capital stock issue in the name of a new company called Gaumont-Franco-Film-Aubert (GFFA).

Léon Gaumont died on 9 August 1946 in Sainte-Maxime-sur-Mèr, in the Provence-Alpes-Côte d'Azur region of France, and was buried in the Cimetière de Belleville in Paris.