The suspicious device found on an Air France flight was a false alarm, say the airline's officials.
The flight from Mauritius to Paris was forced to land in the Kenyan city of Mombasa after a device, suspected to be a bomb, was discovered in a toilet on board.
The Boeing 777, carrying 459 passengers and 14 crew members, was evacuated safely by emergency slides.
Kenyan police spokesman Charles Owino said Air France flight 463 was heading to Charles de Gaulle airport when the pilots requested an emergency landing at the Moi International Airport at 12.37am.
He said "a device suspected to be an explosive" had been found "in the lavatory".
It was the third bomb scare for the French airline in four weeks.
Frederic Gagey, Air France chief executive, said later on Sunday that the device was found to have been made of cardboard and pieces of paper with a timer and "was not capable of causing an explosion".
Passenger Benoit Lucchini of Paris described the emergency landing: "The plane just went down slowly, slowly, slowly, so we just realised probably something was wrong.
"The personnel of Air France was just great, they were just wonderful. So they keep everybody calm. We did not know what was happening.
"So we secured the seat belt to land in Mombasa because we thought it was a technical problem but actually it was not a technical problem. It was something in the toilet. Something wrong in the toilet, it could be a bomb."
The airport was closed during the operation but is now operating as normal.
A Kenyan police official said they had discovered what looked like "a stopwatch mounted on a box".
Kenya's Airports Authority initially said it had foiled a "bombing attempt" and the bomb had been taken to a "safe destination" to be detonated in the morning.
Later they changed their statement to call the device "a suspicious object", removing mention of the word "bomb".
Interior minister Joseph Nkaissery told reporters an undisclosed number of passengers who were aboard the flight were being "interrogated" about the suspect device, but did not say if they were under arrest.
Associated Press later said a Kenyan official had told it that six passengers were being questioned.