Jaan, the flagship restaurant at London's Swissôtel the Howard, has had its three-star rosette rating suspended just days after receiving it.
The hotel's restaurant won its third rosette earlier this month but the award was promptly suspended after executive chef Paul Peters left the hotel.
Peters, who has become head chef at Tudors restaurant at the Marygreen Manor hotel in Brentwood, Essex, said he left to take up a new challenge and move away from fusion Asian cooking.
"I've cooked at Jaan for a year and a half and at Mju before that, so I wanted a change of scene and to get back to French cooking," he said.
AA chief hotel and restaurant inspector Peter Birnie said: "The rosettes have not been lost, just suspended. Our policy is to suspend a rating if there is a major change of circumstances which could potentially affect the standard of cooking.
"We will reinspect after giving the new chef a period of time to settle in."
Peters has been replaced by Simon Duff, formerly head chef at Marriott's Hanbury Manor hotel in Hertfordshire.
A spokeswoman for Jaan said the restaurant's style of modern French cooking with Asian influences would not change, but new menus would be introduced soon.