In 1895 the 26-year-old French engineer Louis Seguin bought a license for the Gnom gas engine from the German firm Motorenfabrik Oberursel. Sold under the French version of the name, the Gnome was a single-cylinder stationary engine of about 4 hp (3 kW) that ran on kerosene (aka paraffin) intended to be used in industrial applications. The Gnome used a unique valve system with only one rod-operated exhaust valve, and a "hidden" intake valve located on the piston head.
On 6 June 1905 Louis Seguin and his brother Laurent formed the Société Des Moteurs Gnome (the Gnome Motor Company) to produce automobile engines. They soon started development of one of the first purpose-designed aircraft engines, combining several Gnome cylinders into a rotary engine. The design emerged in the spring of 1909 as the 7-cylinder rotary Gnome Omega, delivering 50 hp (37 kW) from 75 kg. More than 1,700 of these engines would be built in France, along with license-built models in Germany, Sweden, Britain, the United States and Russia. The Gnome powered Henry Farman's aircraft to take the world records for distance and endurance, was fitted to the first aircraft to break 100 km/h, and powered the first seaplane ever to fly, in 1910.
These events put France to to the forefront of aviation in those years.
In January 1915 Gnome took over Le Rhône, forming the Société des Moteurs Gnome et Rhône.
Sources: https://en.wikipedia.org/wiki/Gnome_et_Rh%C3%B4ne#Gnome, et al