Harrods' owner Mohamed al-Fayed was questioned by police on Wednesday over a newspaper report which alleged he sexually assaulted a 15-year-old girl at his London department store, his spokeswoman said.
Fayed voluntarily went to a police station in west London to answer questions in a 30-minute meeting about the alleged incident that took place in May, reports said.
London's Metropolitan Police said in a statement that a man attended a police station and was questioned under caution "in relation to an allegation of sexual assault that was received in May in 2008 on a girl under 16 at a business premises in central London."
In keeping with British police convention, they did not confirm the identity of the man questioned. There have been no arrests in the inquiry so far.
It is unclear in the police statement whether al-Fayed was questioned as a witness or played some other part in the case.
The Mail newspaper on Sunday reported that a 15-year-old girl had accused an unnamed "senior Harrods executive" of fondling and kissing her after meeting him while shopping with her mother.
Fayed's son Dodi was killed with princess Diana in a Paris car crash in 1997 and Fayed has waged a decade-long battle to expose what he said was the truth about an establishment plot to stop Diana from marrying a Muslim.
The Egyptian-born tycoon, who also owns Premier League soccer club Fulham, has enjoyed a difficult relationship with the British authorities who he says he has distrusted ever since he was cold-shouldered over a request for a British passport.
Fayed, 75, accused Queen Elizabeth's husband Prince Philip of ordering British spies to arrange the car crash in which Diana and his son died. He also said senior British police officers had helped cover this up.
When the inquest into their deaths ended in London in April, the Egyptian-born businessman said he accepted its verdict of unlawful killing, which blamed the couple's chauffeur and pursuing photographers, but he said he had "reservations."