The French Army Ordnance Revolver of 1873 firing 11mm ammunition was developed because of failures in hand guns during the Franco-Prussian war. This design was mass produced and became the standard hand gun of the French Army. In the early 1890s, it became apparent that the Lebel rifle and Berthier carbine were to become the standard infantry, cavalry and artillery arms and each used 8mm ammunition.

Wikipedia:
The Model 1892 revolver (also known as the "Lebel revolver" and the "St. Etienne 8mm") is a French service revolver produced by Manufacture d'armes de Saint-Étienne as a replacement for the MAS 1873 revolver. It was the standard issue sidearm for officers in the French military during the First World War.
The Modèle 1892 revolver is a solid frame revolver with the cylinder on a separate frame swinging right for manual reloading. The Modèle 1892 was first fielded in 1893 and was prominent among French military officers during First World War, and later the French police until the mid-1960s.
A mechanically tight and very well finished handgun, the Modèle 1892 fires 8mm rounds with a striking power equivalent to that of a .32 ACP round. It also features a smaller calibre than many other military revolvers of that time period, including the Webley revolver and its predecessor the MAS 1873 revolver.