The R-5 was a French-made copy of the Sten produced after the 1944 liberation of France. It was built by Gnome et Rhône, a French company best known for making aircraft engines. The Sten was familiar to French forces, as many had been supplied as military aid to the Free French as well as Resistance organizations – and it was also a simple and cheap weapon to make.
In the aftermath of Liberation, there was a lot of political jockeying for power in France. Many different factions had armed themselves during occupation, form the far right to the far left, and everyone wanted to be in a position of power in post-war France. Gnome et Rhône was contracted to make 20,000 of the R-5 submachine guns specifically for the PCF, the French Communist Party (Parti communiste français). The Gaullist government found out about the production and took the guns for itself before any reached the PCF.
The R-5 (named because it was produced in Limoges, in the 5th Region of France as organized during the Resistance) was parts-interchangeable with the standard British MkII Sten, despite having a number of unique features. The R5 used a barrel 60mm (2.5 inches) longer than the standard Sten barrel, a solid wooden stock of the same shape as the MkII, and a vertical front grip inspired by the Thompson. Although missing on this example, it also had a rotating receiver cover that could be used to lock the bolt in the forward position.
Of the 20,000 R-5s ordered, only 8,000 were delivered as best we can tell today. They were used by the military within France and also in Indochina and even into Algeria. In the immediate postwar years France was heavily dependent on US and UK war material, but wanted to equip a larger force than the Anglo-American allies were planning to supply. The R-5 made a useful interim weapon while the French arms industry reestablished itself and eventually developed the MAS-49 rifle family and the MAT-49 submachine gun.
The R-5s were mostly used until utterly worn out, and are extremely rare today. I am grateful for the cooperation of the IRCGN (Institut de Recherche Criminelle de la Gendarmerie Nationale) in having access to film this example for you!