I've seen the following snake (?) near Calvi (on Corsica):
I guess it was about 50cm long.
What is the name of this type of snake?
Great find! Based on the picture and location, I believe this is the Corsican grass snake (Natrix natrix corsa). It is a pretty rare subspecies, and is listed on Annex IV of the European Union Habitat and Species Directive. Worth mentioning that it's nonvenomous.
Photo cred to Frank Deschandol/Philippe Sabine
Unfortunately, I was not able to find too much more info on this subspecies. I know Natrix natrix are pretty widespread throughout Eurasia, but this subspecies is much more restricted.