A good clear photo, so it should be straightforward. I fancy I can see a bulge on the leading (lower) edge of the forewing, which is typical of Chorthippus, and the quite strongly incurved side keels of the pronotum narrow the identification down to a group of species which are usually associated with dry habitats. These include the Common Field Grasshopper, and I have seen and photographed a specimen of that species in this country with a very similar colour scheme to ypur specimen. However, in France there are look-alike species which are not always possible to identify with certainty from photos, especially the females. The commonest of these in France, and the species with the greatest tolerance of moister habitats is Chorthippus biguttulus. It might be that.