The French capital is celebrating the 300 millionth visitor to the landmark Eiffel Tower since its opening in 1889.
To mark the milestone, 1500 visitors were on Thursday evening (local time) given free entry to the first level of the tower, the city of Paris said in a statement.
The 128-year-old wrought-iron structure that was designed by the engineer Gustave Eiffel for the 1889 World's Fair welcomed six million visitors last year.
Following a series of terrorist attacks on the French capital, a screen made out of bulletproof glass has been erected to protect tourists waiting to enter the tower.
Entry to the square under the tower by the banks of the river Seine is also subject to security checks.
France has been under a state of emergency since November 2015 when Islamic State extremists killed 130 people in a series of coordinated attacks on the Bataclan theatre and bars and cafes in Paris.