The man is said to have "jumped up" from the wheelchair and tried to crash the protective glass that surrounds the painting, and then smeared a creamy cake over the famous motif in some form of climate action.
On social media, pictures and videos are spread on the board, which does not seem to have been damaged by the increase, where an employee at the museum wipes the protective glass.
A witness who filmed the incident writes, according to The Guardian, that the man also threw rose petals around him before he was tackled by security guards.
Watch the man smear a creamy cake over da Vinci's Mona Lisa in the clip above.