The occurrence at the Eiffel tower occurred at 23:30 pm (21:30 GMT) on Saturday night.
Armed soldiers who are permanently stationed at the Eiffel Tower surrounded him and ordered him to drop his weapon, which he did without attacking anyone, one security source said, asking not to be named.
In Saturday's incident, the suspect tried to force his way into the secure zone beneath the tower, held out a knife and said "Allahu akbar", the Arabic phrase for "God is great", an official close to the investigation said.
Since previous year, the Eiffel Tower and ticket boxes are only available after you go through metal detectors and check-ins.
The man was arrested and is being held for questioning, and an investigation was opened by prosecutors.
After the arrest, police at the site checked the venue and called for it to be evacuated at around 00:30, 15 minutes before the Eiffel Tower normally closes, the statement added.
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A security source has reportedly claimed that the suspect wanted to attack a soldier.
The man kept was wearing a Paris Saint-Germain football shirt.
France has been on high alert since a series of terrorist attacks in 2015 and 2016 that left more than 230 people dead. The Eiffel Tower was lit up with team colors in celebration of the record-breaking $520 million acquisition of Brazilian star Neymar.
The suspect was born in Mauritania in 1998, but has French citizenship, the official said.
Since the first wave of terror attacks in January 2015, 239 people have been killed.