Very interesting work, thanks.
First observations :
- Map B seems to me like a standard recent FN vote map. Does it differ from such a standard FN vote map somewhere ?
- Map C is more interesting to me. Corsica has its own explanation, for being... you know, Corsica. Other than that two main zones can be spotted : Île-de-France and the borders. Île-de-France abstains the most because of a) immigrants who don't want or don't know how or why to vote, and b) urban way of life with many young people and alternative types. The borders, on the other hand, may be abstaining more than the country as a whole because a number of French people there just work on the other side and their lives are more affected by what's going on on the other side, so they lose interest in French politics. Which would explain why zones such as Genève, Nice, Béarn, Forbach or Maubeuge, widely ranging on the socio-economic spectrum, all tend to abstain more than the country.
For what it's worth, the Genevois and Forbach both have very large immigrant populations as well; the darkest shade of brown on the Haute Savoie border with Geneva is Annemasse, which is very diverse.
On a sort of tangent, is there any reason that so many of the old rural centre-right strongholds have moved to the left in recent decades. I believe the secularisation of Catholic areas has been behind areas like Brittany becoming staunchly on the left, and places like Cantal trending left as well, but there must be some other driving factor, as you wouldn't normally expect rural areas to go left?
