Mona Lisa smeared with cream by disguised man

Videos circulated online of the man urging artists to “think of the Earth” after attempting to break the protective glass around Leonardo da Vinci’s masterpiece. The painting remained unharmed, Louvre spokesperson Nadia Refsi said in an emailed statement confirming the incident.

The Paris prosecutor’s office said by email Monday that it was opening an investigation into the incident after hospitalizing the young man.

One clip showed security guards escorting the man out as he yelled in French, “Think of the Earth. There are people who are destroying the Earth. Think about it. Artists tell you: think of the Earth. That’s why I did this,” according to the Associated Press.

Other clips showed staff cleaning off what appeared to be white cake or cream from the bulletproof protective glass around the 16th-century painting.

The Mona Lisa, housed in one of the world’s most storied museums, has been targeted before.

In 1911, the painting was stolen by a museum employee. In 1956, in two separate incidents, it was hit by acid and a rock, after which the painting was encased in glass to prevent further damage. Decades later, in 2009, a woman attacked it with a ceramic cup, the AP reported.