Air France has a different take on the story.
The airline said the flight had a technical problem after a smoke alarm sounded in the cabin crew rest area.
A statement read: “The cabin crew put on the breathing protection masks to inspect the rest area and no smoke was detected.”
It added that the captain decided to divert to the nearest airport as a “precautionary measure” because the alarm had sounded.
The plane dumped fuel in order to land without the jet being overweight - a standard procedure, it added.
Air France denies reports of panic on board and says that passengers did not leave the aircraft on emergency slides.
“The crew informed the passengers in French, English and Spanish, of the reasons for the diversion.
“The crew reported no injuries, illness or panic among the passengers, who left the aircraft normally using both of the airport’s jetways.”
Following an investigation by the airport fire department on the ground, “no trace of smoke or any other irregularity was found on the aircraft,” the statement added.
The 274 passengers on board were put up in overnight accommodation and continued their journeys on Tuesday afternoon (local time) on another Air France A340 jet.