PARIS: French police on Monday detained a retired policeman over the discovery of a fake bomb on board an Air France flight which made an emergency landing in Kenya, a legal source said.

The 58-year-old man was taken into custody by border police upon his return to France while his wife was also being questioned as a witness, a day after their flight from Mauritius to Paris was diverted to Kenya.

The source gave no further details about the couple, including their nationalities.

A passenger alerted crew members to the device found inside a toilet cubicle on Sunday on board the Boeing 777, which was carrying 459 passengers and 14 crew.

The plane landed in Mombasa where passengers were evacuated using emergency slides before navy and police bomb experts were called in to examine the suspicious item.

The object, made up of cardboard, paper and a kitchen timer, was found to pose no danger to the aircraft or its passengers, Air France chief executive Frederic Gagey said.

He said the “deduction” was that the item had been placed in a toilet cupboard by one of the passengers and said the bomb scare appeared to be the result of a “bad joke.”