France began work developing a semi-automatic service rifle shortly after the adoption of the Lebel Model 1886 and the 8 mm Lebel cartridge. It spent almost two decades testing various rifle designs and cartridges, eventually choosing the Meunier rifle in 1910 chambered for 7 mm ammunition. However, the French arsenals continued to debate what cartridge it would use, taking until 1912 to make a decision on the case length (resulting in a 7 mm x 59 mm cartridge) and until 1913 to determine the loading. MAS Arsenal began gearing up to produce 5,000 Meunier rifles per month in Spring 1914, but the outbreak of World War I meant that very limited numbers were produced (around 1,000 prior to 1916 and 4,000 during 1916). In 1916 France adopted the Fusil Automatique Modèle 1917 (also known as the RSC 1917). The Model 1917 used 8 mm Lebel ammuniton and many components from the Lebel Model 1886, allowing a total production of 86,000 rifles, but it was considered to be a bulky weapon for trench use and had an inconveniently placed gas port that required constant cleaning. The RSC 1917 was issued at a rate of sixteen rifles per infantry company from Summer 1917. An improved Model 1918 design revised the gas port and was found to be more accurate than the Model 1886 and Model 1917 rifles, but it only saw production in November 1918 and so saw very limited production of 4,000 rifles. If the war had continued it was planned for the RSC 1918 to replace all French infantry rifles starting in 1919 (source). Despite this extensive experience with semi-automatic rifles, there doesn't seem to be any indication that the RSC series rifles saw any service in World War II. France didn't begin to replace the Lebel Model 1886 until it adopted the MAS-36 in 1936, but the MAS-36 only started production in late 1937 and so ironically enough large numbers of Model 1886 rifles saw service again in World War II. What would it take for France to have adopted the Meunier, RSC, or other semi-automatic rifles, and how might it have changed the French Army and overall military strategy? Could France have developed modern infantry tactics based around semi-automatic infantry moving using the Chauchat and/or FM 24/29 light machine gun as a base of fire?
Here's a photograph of the Meunier rifle from Forgotten Weapons. There's a whole gallery of images of it here. Here's a photograph of the 7 mm x 59 mm cartridge, along with a vintage cartridge box and clip (source).