The body which runs the site, Société d’exploitation du monument (SETE), said bomb disposal experts as well as police were scouring the area, including a restaurant located on one of the floors.

“It’s a usual procedure in this kind of situation which however is rare,” a spokeswoman said.

Visitors were evacuated from both the three floors and the square under the monument shortly after 1:30 pm (1130 GMT).

The evacuation was ordered “following a bomb threat”, a police source told French newspaper Le Parisien on Saturday. The evacuation was a “precautionary measure”, and the source of the bomb threat was not yet known, the source added.

Construction work on the tower began in January 1887 and was finished on March 31st, 1889. It received two million visitors during the World’s Fair of 1889.