On Sunday, a wig-wearing man dressed as an old woman in a wheelchair threw a cake at the Mona Lisa, which coated the protective glass case with white cream but did not damage the painting.
The man pretended to be disabled to get a wheelchair and approach the painting, a Louvre museum spokeswoman told the dpa news agency.
When he was close enough to the most famous painting in the world, he threw a hidden cake on the window, she added.
Immediately after the incident, Louvre security guards were filmed escorting the man out of the museum as he shouted in French: “Think about the Earth… There are people who are destroying the Earth.”
The Paris prosecutor’s office on Monday identified the cake thrower as a 36-year-old man. He was detained and placed under psychiatric evaluation.
An investigation has been opened into the damage to cultural artifacts.
The Mona Lisa was placed behind a protective case in the 1950s after being damaged in an acid attack by a vandal.
In 2009, a woman threw a glass cup at the board, shattering the cup, but without damaging the case or the paint.
The Mona Lisa is on permanent display in the Louvre, which became the property of France after its acquisition by King Francis I in the 16th century.
wmr/msh (dpa, AFP, AP)