French windows are essentially still windows though they appear to be like doors. To find the right window treatment for them would be first to maintain a consistency with the rest of the room and to make sure that the view is not blocked. French window is popularly covered with sheers though some may not like that idea.
Blinds or shades will work with this kind of window but the main idea is to make sure that they don't flap or move when the windows are operated. To avoid that we could use some kind of hold down brackets at the base that will prevent this from happening.
