Soon after news of the fatal crash broke, agents working for the DGSE (Direction Générale de la Sécurité Extérieure), the French equivalent of MI6, were dispatched to Brazil.
It was there that they established that two names on the passenger list are also on highly-classified documents listing the names of radical Muslims considered a threat to the French Republic.
A source working for the French security services told Paris weekly L’Express that the link was “highly significant”.
Agents are now trying to establish dates of birth for the two dead passengers, and family connections.
There is a possibility the name similarities are simply a “macabre coincidence”, the source added, but the revelation is still being “taken very seriously”.
So far 47 bodies have been recovered.