Aboukhater closed the purchase deal with Morgan Stanley Real Estate Fund on Monday, the source said.
The portfolio includes Intercontinental-branded hotels in Vienna, Amsterdam, Madrid, Rome, Frankfurt and Budapest in addition to the landmark Carlton hotel.
The Lebanese businessman has owned the Grand hotel in Monte Carlo and the Dorchester in London.
Agence France Presse quoted Didier Boidin, the deputy head of the Intercontinental group in Western Europe, as saying that "the change of the owner won't change a thing in the current administration."
"Intercontinental will continue to manage the Carlton hotel," Boidin said.