Two protesters on Sunday hurled soup at the bullet-proof glass protecting Leonardo da Vinci's "Mona Lisa" in Paris, demanding the right to "healthy and sustainable food", an AFP journalist saw.
The action, which comes as French farmers protest across the country, is the latest in a string of similar attacks against artworks to demand more action to protect the planet.
Two women on Sunday morning flung streams of red and orange soup onto the glass protecting the smiling lady to gasps from the crowd in the French capital's Louvre museum.
"What is more important? Art or the right to healthy and sustainable food," they asked, standing in front of the painting and speaking in turn.
"Your agricultural system is sick. Our farmers are dying at work," they added, before security staff placed black screens in front of them and evacuated the room.
A group called Riposte Alimentaire ("Food counterattack") claimed responsibility for the stunt.
In a statement sent to AFP, they said the soup throwing marked the "start of a campaign of civil resistance with the clear demand... of the social security of sustainable food".
The action comes as French farmers have been protesting for days to demand better pay, taxes and regulations.
The government has been trying to keep discontent among the agricultural workers from spreading months ahead of European Parliament elections, which are seen as a key test for President Emmanuel Macron's government.
Prime Minister Gabriel Attal on Sunday scrambled to announce new measures as some farmers threatened to block roads into the capital on Monday.
The action at the museum follows a series of such stunts by climate activists against world-famous paintings to demand more action to phase out fossil fuels and prevent global warming.
In October 2022, two activists from the Just Stop Oil group grabbed headlines when they splashed tomato soup over the glass protecting Dutch artist Vincent van Gogh's "Sunflowers" at the National Gallery in London.
The "Mona Lisa" has been attacked several times before.
A man threw a custard pie at her in May 2022, also saying artists were not focusing enough on "the planet". Her thick glass casing ensured she came to no harm.
She has been behind glass since a Bolivian man threw a rock at her in December 1956, damaging her left elbow.
The glass was made bulletproof in 2005.
In 2009, a woman threw an empty teacup at the painting, which slightly scratched the case.
