The last remaining colony by a European power in continental South America (although France integrated French Guiana into the French state as a full departement, so it is technically no longer a colony).
French Guiana is noted for two things: Kourou, the site of the European Space Agency's spaceport, and the fact that it was votes from French Guiana that narrowly decided a 'yes' vote on the French referendum to pass the Maastricht Treaty. And also for the fact that nothing ever, ever happens to it in future history TLs; whether the EU conquers the world, is conquered by Russia or the Obligatid Caliphate, or gets sucked straight into the CERN LHC, French Guyana cheerfully soldiers on as an overseas department of France.
None that we know of.
French Caribbean overseas territories - Caribbean overseas territory of France.