Wikipédia says that people in France mistakenly call these insects « cousins » — yes, "cousins" — that being a popular name given to mosquitoes. Interesting image, that — cousins as pests that suck the blood out of you. In this case, this is not a mosquito, and it won't bite or sting you. It's a fly — a crane fly in English, both in Britain and America, it seems. I guess we've all seen them often in our lives. In French, the crane fly is more correctly called une tipule (a member of the Tipulidae family of flies, from what I've read).
This one landed on our terrace door yesterday morning. I noticed it when I opened the curtains for Tasha so that she could watch the birds through the glass. Then I grabbed my camera. It seems to be a male because its abdomen is not pointed (if I understand the Wikipédia article correctly). The females have a pointed abdomen, the back end of which is their ovipositor. The crane fly larvae are pests, eating the roots of plants and sometimes the leaves.
Wikipédia also says that there are 4,000 species of crane flies in the world — 200 in France alone, and nearly 500 in all of Europe. Note that that's the number of species, not individuals. It's surprising we don't see them even more often.