All right, I'll bite. What is a sedevacantist?
A sedevacantist is someone who claims that the See (Sede) of Peter is vacant i.e. that the Pope is not really the Pope. He is an invalid claimant to the office.
A sede vacantist is one who believes the seat of St. Peter, i.e. the Pope, is vacant. They believe the Popes of recent times are not valid Popes, hence the seat is vacant.
You will find a few, not many, in France, but most traditionals fall under the umbrella of SSPX. SSPX is NOT sede vacantist. They still believe the Pope exists.
8mm