In 1905, he started working on a new model of carburettor equipped with two fuel nozzles, the second of whom allowed the mixture to keep the same ratio independently of the engine speed.

[1][4] Zénith carburettors being in high demand, with 2,740 items manufactured in 1907–1908, and production licenses sold to Cottin & Desgouttes, De Dion-Bouton and Peugeot, Rochet-Schneider decided it was time to create a new company, and thus Société du carburateur Zénith was created in July 1909 as a société anonyme.

The Zenith Carburettor Company of Stanmore, London, England, followed suit in 1912; and finally a last subsidiary was created in Turin, Italy, in 1916.

[6] With such riches flowing, the company was able to afford the services of architect Louis Payet, who designed a majestic gate for the Lyon factory in 1913, opening on a steel and glass industrial style long gallery.

[7] World War I led Zénith to diversification, as it started producing carburettors for airplanes and military vehicles.

While retaining his trademark glasses and long beard, the prof. sports a French Army military uniform on 1914–1918 advertising material.

[8] Their industrial policy turned into success, as Zénith products went on to be offered by the main auto makers of the time, both French and foreign.

[6] As an example, at the 1924 Lyon Auto show, half the cars exposed were fitted with Zenith carburettors, while the rest had theirs made by 19 different manufacturers.

Roaring Twenties Zénith adverts tried to present the carburettor as a key ingredient to the motorist's pleasure, while showing driving ladies, holidays, and even stars such as Hollywood actress Pearl White.

In 1921, Zénith introduced a "triple diffuser" carburettor, aiming to improve the fuel/air mixture homogeneity and thus fuel economy.

Unfortunately, this implied an important carburettor size, plus high production costs, which led to the triple diffuser being abandoned after a few years.

As carburettors became increasingly complex, research became costly, so they reached an agreement with the American Bendix Corporation, under the terms of which they would put in common their laboratories and experience.