Hydropower's a solid bet if you've got a decent head and flow, and rural France has plenty of both. The catch is that unlike solar, it's brutally site-specific: a small turbine's output scales with head (drop height) times flow, so a stream dropping a few meters can beat a whole array of panels, but one that barely falls means almost nothing. Do you know roughly your head and flow yet? That'd tell you if it's worth it before you spend a euro.