Yes, Corsica is French territory but it's not a usual political borough called "région" - but a "territorial collectivity" which means it has greater autonomous political powers. There's also many Corsican nationalist movements which don't see Corsica as a part of France but as an independent country. But I don't know how strong these kind of views are among the people. I've only been to one course dealing contemporary France so I'm by no means a professional on this matter. I don't excatly know how it was during the times it was driven as "Rallye De France", atleast I don't remember any major problems with it. These are "small" things with bigger political perspective, just like Mikkelsen's car mysteriously happened to carry regular Skoda colours instead of Union Jack painting in Circuit of Ireland driven in Northern Ireland...