Thieves stole four paintings from the Renoir Museum on the French Riviera early on Tuesday, dropping one as they made their getaway.
The raiders broke into the museum shortly before 6am, Cagnes-sur-Mer mayor Bryan Masson said on his Facebook page.
The mayor did not identify the works stolen, but French media reports say they have an estimated value of €9 million ($10.4 million).
Police spotted the thieves and gave chase, during which they dropped one painting but escaped with the other three, Mr Masson said.
“Attacking the Renoir Museum is attacking a part of the history and heritage of Cagnes-sur-Mer. These actions are particularly serious,” he wrote.
The museum was created in 1960 in the mansion of the Impressionist painter Pierre-Auguste Renoir on a hill in Cagnes-sur-Mer, near Nice, where he died in 1919.
The collection on display in the museum includes 13 Renoir paintings, as well as about 40 sculptures, photographs and pieces of furniture.
The master's most valuable works have fetched millions of dollars at auctions in the past.
Art thieves in Europe are committing more violent robberies, and specialist gangs have been replaced by ad hoc opportunists recruited through social media, Europol said in a recent report.
The EU’s law enforcement agency said thieves are using explosives, axes and sledgehammers, with the heist at Louvre Museum in Paris last October last as an example. The thieves threatened guards and visitors, and stole €88 million ($102.3 million) in jewels including Empress Eugenie's tiara.
The agency traces the trend back to 2024, when four hooded criminals, equipped with baseball bats and axes, stormed into the Cognacq-Jay art museum in Paris. They took seven objects adorned with gold and diamonds before fleeing the scene.
Explosives were used in the Netherlands in the same year, when a gang broke into the Drents Museum in Assen.
