Passengers at Paris' Charles de Gaulle Airport's Terminal 2F were evacuated without warning on Saturday evening.
Charles de Gaulle is Paris' largest airport.
There was no warning and most passengers were not immediately told why they had to evacuate.
Authorities later announced that there had been a security incident and the evacuation was in compliance with "security rules."
"Everybody evacuated at the Charles de Gaulle airport into the departure area. NO word on what is causing the evacuation," one person tweeted.
Meanwhile "Paris Aeroport" tweeted, "In order to comply with security rules, terminal 2F was temporarily evacuated. Boarding will gradually resuming (sic)."