Border guards at Paris' Charles de Gaulle airport detained one of the passengers on an Air France flight over a bomb hoax, after he arrived back in France on Monday, authorities investigating the case said.
Flight AF463 was headed from Mauritius to Paris on Sunday with 473 people on board when a passenger discovered a suspicious object. The plane was subsequently diverted to the nearest airport, which was Mombasa in Kenya.
One passenger is currently in police custody for his suspected involvement in planting a fake bomb, the public prosecution service in the Parisian suburb of Bobigny confirmed on Monday.
According to broadcast reports on BFMTV and France Info, the suspect is thought to be a former policeman.
The authorities did not give further details, but confirmed that an investigation had been opened into the bomb hoax, which Air France said had put lives in danger.
The airline said earlier on Monday that it is seeking to press charges against whoever had planted the mock device - made of paper, cardboard and a kitchen timer - in the plane's lavatory.
A spokesperson confirmed that the Air France desk at Charles de Gaulle airport had filed a complaint to the state prosecution service in Bobigny.
The 459 passengers and 14 crew were flown back to the Paris airport one day after they were forced to land in Mombasa.
Air France chief Frederic Gagey said on Sunday that there was no evidence of a safety breach on Mauritius, which is a favourite holiday destination for French nationals because a large part of the Indian Ocean island's population can speak French.
The device did not contain any explosives and was therefore not detected by security officials there, Gagey said.