The organisers of the 2016 Rio Olympics have denied that vote buying helped to secure the Games after a French newspaper reported that a Brazilian businessman made payments to the son of an IOC member before the vote.
Le Monde reported that a payment of 1.5 million dollars was made to Papa Massata Diack, the son of Lamine Diack.
Rio lost the first vote to Madrid but bounced back to win the nomination on a third ballot, by 66 votes to 32.
A spokesman for the Rio 2016 Games said the allegations did not affect the choice made by IOC delegates to award the Games to Rio.
Rio became the first South American city to host the Olympic games in August.