A man, believed to be Russian, who sparked a mass evacuation of the Eiffel Tower by scaling the iconic Paris landmark has been admitted to a psychiatric unit, legal sources said Tuesday.

The man caused chaos Monday and the closure of the monument to tourists by spending six hours clinging to the outer metal framework of the Eiffel Tower.

His identity has not been disclosed. He was questioned by police on Tuesday and has now been admitted to the psychiatric hospital of the police, legal sources told AFP.

An investigation has been opened for unauthorised entry into a cultural monument, a judicial source said.

"It is a Russian man who has suicidal tendencies," said a source close to the case, asking not to be named.

Firemen who had rappelled down from the tower's third-floor observation deck to near the black-clad climber managed to persuade him to come down.

Some 2,500 people who had come to visit the Eiffel Tower had to be evacuated Monday but it reopened as normal on Tuesday.