Magnificent, great work. My knowledge of French politics is generic and I'm pretty much ignorant of the vote dynamics and geography in the 90s. For sure there is people on more able than me to see the cleavages on this map. At first glance, it surprises me a bit the green in Alsace-Lorraine and the adjoining Moselle. Looking at the map, it appears that Bordeaux and the Gironde voted against the Maastritch Treaty, but I'm not sure if that result is "normal" for that place and in that time.
In the Gironde, it's not so much Bordeaux itself but a combination of the Entre-Deux-Mers, which is the area between the Garonne and Dordogne rivers North-East of Bordeaux; as well as the Médoc (along the left bank of the Gironde) and the Bassin d'Arcachon.
The Entre-Deux-Mers is the kind of down market, mid-to-low income exurban area that is exactly the kind of place the Gilets Jaunes sprung from; which should explain things.
The Médoc is mostly famous for the wine, but it also a big hunting area. Like the Seine and Somme estuaries, it has a big tradition of waterfowl hunting, and that seems to go hand in hand with reactionary politics wherever you go in the world (it shows up less around the Somme and Seine because there are other factors in that region...). Also, IIRC the wine industry creates some pretty weird class structures of its own.
Not too sure about the Bassin d'Arcachon. It's mostly huppé BCBG tourist resorts as far as I know.
With Alsace; it is a pretty wealthy area - being in the heart of Europe rhénane and all, and Strasbourg has the European parliament as well. But in particular, like the whole France-Germany and France-Switzerland border area, it has profited a lot out of European integration; in particular with people being able to commute over the border to high paying jobs. Notice how the only red along that whole border area (not with Belgium, of course), is in some
really remote areas in the Jura. Specifically, its the bits bordering La Brévine and the Franches Montagnes/Ajoie regions in Switzerland, which are the bits of the Jura that are too remote to even have any watchmaking industry - and therefore not many jobs for frontaliers.
Also might have some degree of the "Europe as a catholic project" ideal hanging on.
