Where are the window screens?

I have discovered the singular worst thing about France. They don't have window screens! Maybe somewhere - but not in this neighborhood. But, they do have mosquitos. Thus, every night is a damn battle with the mosquitos buzzing around our heads. We are all getting bit at an alarming rate but it is too warm to not open the windows. So, if you are planning to visit, you might want to pack your mosquito netting...