The International Olympic Committee has refused to comment on claims that the successful Tokyo Olympic bid team made a "seven-figure payment" to an account linked to the son of former world athletics chief Lamine Diack.
The Guardian alleges a payment of about £1m was paid into the account during the race to host the 2020 Games.
In March, French prosecutors investigating corruption in athletics widened their scope to include the bidding and voting processes for the hosting of the 2016 and 2020 Olympics.
The British newspaper says French police are believed to be studying the allegation.
In a statement, the IOC said it had been "in contact with the French magistrates in charge of the investigation on the IAAF [athletics' world governing body] case, and with Wada [World Anti-Doping Agency], since its start".
It added: "The IOC's chief ethics and compliance officer will continue to be in contact with all interested parties to clarify any alleged improper conduct. The IOC will not comment any further on the elements of the investigations at this stage."
Tokyo bid already being looked at
The Tokyo bid first came under scrutiny in January when the second part of a Wada commission report into corruption included a footnote detailing a conversation between another of Lamine Diack's sons, Khalil, and Turkish officials heading up the Istanbul bid team.
A transcript of the conversation cited in the report suggested a "sponsorship" payment of between $4m and $5m (£2.8m and £3.4m) had been made by the Japanese bid team "either to the Diamond League or IAAF".
The footnote claims the Istanbul bid "lost Lamine Diack's support because they did not pay".
Wada's independent commission said it did not investigate the claims "for it was not within our remit".
A Tokyo 2020 spokeswoman described the note in Wada's report as "beyond our understanding", adding that "Tokyo's bid was about Japan's commitment to address issues around the integrity of sport".
What is the background?
Lamine Diack, the former president of the IAAF, is already being investigated by French authorities. He was arrested last year on corruption and money laundering charges, over allegations he took payments for deferring sanctions against Russian drugs cheats.
His son Papa Massata, who was employed by his father as a marketing consultant for the IAAF, is also under investigation, and a warrant for his arrest has been issued by Interpol.
Diack Jr has been banned for life by the IAAF but told the BBC in December he and his father were innocent of the claims against them.
The IOC overhauled its rules - and regained trust in the integrity of its bidding process - since the 1999 Salt Lake City bribery scandal exposed systematic corruption.
In February, Wada commission chief Dick Pound said he was "fairly certain" the IOC was free of organised corruption, but just a month later the French prosecutors opened their investigation into the bidding processes for 2016 and 2020.