A framegrab taken from an AFP video shot in Paris on April 25, 2024. AFP
No one was hurt and there was no risk of further collapse, while the cabaret will reopen on Thursday evening.
While the reason for the accident was not yet known, the Moulin Rouge's director Jean-Victor Clerico said there was no sign of "foul play", adding the cause was "obviously a technical problem".
"We'll rise to the challenge," Clerico said, adding that "the Moulin Rouge is 135 years on, so it's seen all kinds of things".
The incident around 1:45 am (2345 GMT on Wednesday), after the nightspot closed, comes as the countdown to the July-August Olympic Games is ticking with millions of visitors expected.
Hundreds of thousands of people watch the Moulin Rouge's daily shows each year, with many more stopping to look from the outside at the landmark at the foot of the Montmartre hill.
The collapse would "especially move the showbusiness world and everyone who loves Paris," Culture Minister Rachida Dati posted on X, formerly Twitter.
Paris mayor Anne Hidalgo told AFP she felt "great pain" at the damage to a landmark "famous the world over".
"We're putting everything into getting the sails back onto our iconic windmill as quickly as possible," the Moulin Rouge said in a statement, with both city hall and the culture ministry offering help.
The sails had been rebuilt two decades ago to make them lighter, director Clerico said, adding that there are checks every two months -- the most recent on March 20.
An AFP journalist saw workers loading the slightly twisted sails of the windmill into the bed of a truck for removal, while barriers were set up around the Moulin Rouge.
The letters M, O and U had also toppled from the name spelt out on the building's facade.
"I can't believe it," said Exauce, a cook at the cabaret who asked not to give his second name.
He saw the sails on the ground as he arrived for work around 8:00 am.
"It's as if the top had been chopped off the Eiffel Tower, it hurts me," said Daniel, a 58-year-old who said he passes the Moulin Rouge every day on his way to work.
"I hope they repair it soon," he added.
600,000 visitors annually
The Moulin Rouge, with its distinctive red windmill sails built of wood and metal, is located in northern Paris and is one of the most visited landmarks in the city.
Director Clerico said there would be "no impact" on the Moulin Rouge programme from the sails' fall.
Around 600,000 people each year watch its two daily shows held year-round, keeping 450 staff in work.
Known as the birthplace of the modern dance form the can-can, it opened its doors in October 1889 at the foot of the Montmartre hill.
It quickly became a hit and a stop to look at its facade or catch a show inside is a must on most tourists' checklist for the French capital -- especially since the eponymous 2001 film by Baz Luhrmann.
The only serious accident the landmark has endured was a fire that erupted during works in 1915, which forced the venue to close for nine years.
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