The Michelin Guide announced Monday the shock decision to knock a star off the Paris restaurant of Guy Savoy, frequently named the best chef in the world.
The 69-year-old has held Michelin's top three-star status since 2002 for his Monnaie de Paris restaurant overlooking the Seine, which has a sister version in Caesars Palace, Las Vegas.
In November he was named best chef in the world for the sixth year running by La Liste, which aggregates thousands of reviews from around the world.
Savoy's fame goes beyond the kitchen as an ambassador for the French "art de vivre" -- he has pointedly rejected the fad for non-alcoholic drinks, for instance -- and he lent his voice to the French version of Pixar film Ratatouille.
But that has not stopped Michelin downgrading his establishment to two stars in its latest edition, published next Monday.
It did the same for the upmarket seafood eatery of Christopher Coutanceau in La Rochelle.
"These are exceptional restaurants, so you can imagine that these decisions are carefully considered, supported by numerous visits from our inspectors throughout the year," Gwendal Poullennec, head of the guide, told AFP.
The reasons are not made public, and communicated only to the chefs involved.
"For such important decisions, we include not just French inspectors but also some from other countries," said Poullennec.
The move to downgrade restaurants is always hugely controversial, especially since the suicide 20 years ago of Bernard Loiseau -- a close friend of Savoy -- after his restaurant lost a star.
One chef, Marc Veyrat, unsuccessfully took the guide to court in 2019 after being stripped of a star, and said he never again wanted to see a Michelin inspector in his restaurants.
Around 20 French restaurants have also been downgraded from two to one star in the latest edition of the guide.
It had not downgraded anyone since 2019, conscious of the difficulties caused by the Covid-19 pandemic.
Those difficulties have continued with restaurants facing staffing shortages and, in the last year, soaring prices.
But the guide says downgrades are now necessary if it is to stay relevant.
"Yes, there are challenges, but they are challenges for everyone," said Poullennec.
Created in 1900 by tyre manufacturers Andre and Edouard Michelin as a guide for motorists, it now has editions across Europe, Asia, North and South America.