No need for that. Legionaires are non-French volunteers fighting for the French. Mercenaries, in other words.
It's not really their government, it's just their employer.
The motto of the FFL:
The Legion is our Country. The FFL grows its own food, makes its own wine, retires men to its own farms, and in many ways is a "nation within a nation."
In the early 1980s I had occasion to be hanging around bars in Africa frequented by Legionnaires, in Djibouti and N'Djamena. While most of them were foreigners, there were a number of Frenchmen among them. I met one Brit, who had been a member of The Parachute Regiment. He found life there rather tame, and when his enlistment in the British Army was up, he went to Marseilles and joined the Legion. He had been in Beirut in Oct 1983 when the heathens blew up those 241 Marines and fifty-some French paras. He was liaising between the Legion and the Marines there.