Monaco has denied that it pays no fee to host the fabled street race in the principality.
The race is commonly called F1's 'jewel in the crown', amid rumours that its history and status meant it was the only event on the annual schedule that is charged no fee.
"That's just a rumour," Monaco's Prince Albert II told FIA magazine Auto.
"Maybe the rights are less expensive than for other circuits, but there is a fee."
The prince's comments come after the now-ousted F1 supremo Bernie Ecclestone recently admitted that he overcharged some race promoters, but now it is confirmed that Ecclestone actually under-charged Monaco.
Prince Albert II said: "Bernie was well aware what Monaco brought to Formula 1 - he said it himself, as do the sponsors and drivers. He always took care of us, but he still made us pay what he reckoned was the right amount."
This year's Monaco Grand Prix will take place on May 28.