It wasn't immediately clear why the man had attempted to climb the tower or how he got past the monument's security.
"The Eiffel Tower has been closed and is in the process of being evacuated because a person is scaling it", a spokeswoman for the landmark said.
Police do not yet know why he began his ascent up the iron beams, a source told AFP. An unidentified official said that police personnel have communicated with the climber but are yet to ascertain his motive. It advised visitors to postpone their visit.
The esplanade underneath the monument was also evacuated, as was a large section of the adjacent Champ de Mars park.
The record is held by Alain Robert, known as the "French Spiderman", who illegally climbed the whole Tower in 1996, reaching the top in 45 minutes.
"Just having a picnic in the park when we notice there is literally a guy dangling from the Eiffel Tower", another said.More news: Private contact data of millions of Instagram users was reportedly exposed
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Police prevent tourists from entering the area surrounding the attraction. The official said the man was "under control and out of danger" Monday night.
According to reports, a man began climbing at the second level, which is approximately 149 meters above the ground level.
The closure comes less than one week after the Eiffel Tower celebrated its 130 anniversary with an elaborate light show.
Firemen had rappelled down from the tower's third-floor observation deck to try to reach the climber, who was dressed in a black jacket.
Roughly six million people visit the tower every year.