[4] When the Salon Carré, where the Mona Lisa hung, was empty, Peruggia lifted the painting off the four iron pegs that secured it to the wall between Antonio da Correggio's Mystical Marriage and Titian's Allegory of Alfonso d'Avalos and took it to a nearby service stairway of the Sept Mètres.

There, he removed the protective case and frame, hiding the discarded elements behind some student artworks stored on the staircase landing.

"[4] Two Germans, the poet Guillaume Apollinaire, and the painter Pablo Picasso were arrested,[9][10] and all passengers of an ocean liner set to sail were also searched.

During this period, officers visited Peruggia's apartment and questioned him twice about his possible involvement; he was not considered a primary suspect.

Knowing that a story could sell millions of copies, newspapers offered financial rewards for information, and for over two years, hundreds of false leads were sent to the police and the press.

[4] A witness described being "in the company of numerous other curious visitors, to stare at the empty space on the wall of the Louvre where the famous lady had hung.

"[4] After keeping the painting hidden in a trunk in his apartment for two years, Peruggia returned to Italy with it by train, after he saw adverts by antique dealers in an Italian newspaper.

While the painting was famous before the theft, the notoriety it received from the newspaper headlines and the large scale police investigation helped the artwork become one of the best known in the world,[4] gaining considerable public interest.

[16] Perhaps sincere in his motive, Peruggia proclaimed "I am an Italian and I do not want the picture given back to the Louvre",[17] and may not have known that Leonardo da Vinci took this painting as a gift for King Francis I when he moved to France to become a painter in his court during the 16th century, 250 years before Napoleon's birth.

"[19] The following year, he wrote: "I am making a vow for you to live long and enjoy the prize that your son is about to realize for you and for all our family.

"[20][21] Put on trial, the court agreed to some extent that Peruggia committed his crime for patriotic reasons and gave him a lenient sentence.

This, alongside popular pressure, had the effect of inducing the court to grant him extenuating circumstances and to impose the lenient sentence.

[4] If he wanted to make money from a theft, he could have stolen from the Louvre a 140-carat diamond or take gold objects to melt them, without ever being caught.

[4] At the same time, money were on his mind, and his notebook before the theft contained names of billionaires like John D. Rockefeller and Andrew Carnegie, and traveled to London to try to sell the Mona Lisa,[10] as also evidenced by the court trial, where it was revealed the dealer Duveen had laughed at him.

[17] Another theory later emerged, claiming the theft may have been encouraged or masterminded by Eduardo de Valfierno, a con man who had commissioned the French art forger Yves Chaudron to make copies of the painting so he could sell them as the missing original.

[23] Peruggia's theft is part of popular culture, and over the years it has been celebrated in books, films, and songs including the "Mona Lisa" written in 1978 by Ivan Graziani.

[30][31] The small original silver gelatin print (123 x 54 mm) had been estimated by photography expert Jean-Mathieu Martini at between €1,500 and €1,800, excluding fees.

In the 2024 Summer Olympics opening ceremony, the theft is referenced by the Minions when they stole the Mona Lisa painting from its protective chamber.