Last updated on .From the section Olympics

Rio won the right to host the Games by 66 votes to 32

French investigators think the vote to give Rio the 2016 Olympic Games may have been rigged, it is claimed.

A Brazilian businessman paid $1.5m to the son of an influential International Olympic Committee (IOC) member just days before the host city was chosen, according to French newspaper Le Monde. external-link

"The French justice suspects that this money may have been used to influence the votes," it says.

Rio 2016 organisers say the vote was "clean".

The Brazilian city won the right to host the Games by 66 votes to 32.

The IOC has confirmed an ethics commission is looking into the allegations and it is "working in co-operation with the [French] prosecutor".

Le Monde says investigators have established a holding company belonging to the businessman paid the money to a company set up by Papa Massata Diack, a French-Senegalese marketing consultant who is banned for life from athletics for alleged corruption, and who is also the subject of a 'red notice' issued by Interpol.

It was also alleged a payment was made to former Namibian sprinter, IOC member and IAAF Council member Frankie Fredericks.

"He informed the IOC and explained the situation and emphasised his innocence immediately upon being contacted by the journalist," added the IOC statement.

"Immediately after a link was made between this contractual payment and the vote for the host city, Mr Fredericks himself also turned to the IOC Ethics Commission, which is now following up on all the allegations in order to fully clarify this matter."

Fredericks won double Olympic silver medals over 100m and 200m in the 1992 and 1996 Games.

Papa Diack is the son of former IOC member and president of athletics' governing body Lamine Diack, who is being held in France on corruption charges.

The Brazilian businessman named by the newspaper subsequently won a number of construction contracts with the state of Rio related to building infrastructure for the Games.

French prosecutors announced last year they were widening their investigation into corruption in athletics to include the bidding and voting processes for the hosting of the 2016 and 2020 Olympics.