French judges are investigating whether $4.5m was paid by the organisers of the 2019 World Athletics Championships in Qatar to a controversial former senior figure in athletics’ governing body, the IAAF, hours before Doha won the right to host the event.

A proposal to pay $4.5m, which has never been publicly revealed, is shown in documents seen by the Guardian, the French media company Mediapart and the German news magazine Der Spiegel. It would have led to the organisers buying the right to keep revenues from ticket sales and from national sponsors in Qatar in exchange for a series of payments to the Sporting Age, an off-shore company in Singapore with close links to the former IAAF marketing executive Papa Massata Diack.

The proposal was found in a tranche of documents unearthed in a police raid on the IAAF headquarters in Monaco. Those documents include emails and letters describing negotiations by Qatari officials before the vote to award the championships on 18 November 2014. The negotiations were with Diack and his father, the former IAAF president Lamine Diack, who are both due to stand trial on corruption charges next year in Paris.

Lamine Diack is being held in France. Papa Massata Diack, who was banned from athletics for life in 2016, is a fugitive in Senegal. Both men deny the charges. The International Olympic Committee said in a statement it had been told by Senegal’s president, Macky Sall, that his country would “fully cooperate with the French judicial authorities’ investigations”.

The Guardian, Der Spiegel and Mediapart have seen a draft and unsigned contract drawn up in February 2015, which sets out how the $4.5m mentioned in an 18 November 2014 letter would be paid in instalments. That draft contract was also discovered during the ongoing investigation by the French investigating judge Renaud Van Ruymbeke, which has now been taken up by his colleague Bénédicte de Perthuis.

Papa Massata Diack, who is the subject of an Interpol arrest warrant after being accused of corrupting the bidding processes of a number of IAAF world championships and Olympic Games, denied any wrongdoing. He told the Guardian he had a “full mandate” to negotiate on behalf of Dentsu, a Japanese marketing company. In an unsigned document, it was proposed the IAAF should grant Dentsu the commercial rights to the world championships but that “Dentsu has indirectly granted the rights to TSA [the Sporting Age].”

Facebook Twitter Pinterest Papa Massata Diack said he had a ‘full mandate’ to negotiate deals. Photograph: AFP/Getty Images

The IAAF said in a statement any contracts signed by it were part of the French investigation and so it was not able to comment. However it added “it is important to note that sponsor and broadcast commercial partnerships are signed with Dentsu who own the marketing and commercials rights” and that the Sporting Age received no money in those contractual payments.

The organisers of the Doha bid did not respond to a number of questions. Dentsu also did not respond to a request for comment. The Guardian has been unable to confirm whether or not a $4.5m payment was made.

According to other documents seen by the Guardian, the Sporting Age received $4.3m in September 2014 from the Beijing 2015 World Athletics Organising Committee, under a contract for the purchase of national rights similar to the one negotiated with Doha. The Beijing committee did not respond to requests for a comment.

Papa Massata Diack did not deny his close links to the Sporting Age and told the Guardian: “My contract with [the] IAAF did not cover receiving any payment on behalf of the IAAF and I have never done so,” he said. “As of the French investigation on marketing, sponsorship and TV activities my stance is very clear. They have no legal jurisdiction to investigate contracts under Swiss, Monaco or Japanese laws. The French investigation seems to be trying to audit the full 16 years of Lamine Diack leadership.”

Lamine Diack, through his lawyer, said he did not want to comment.

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Both Diacks are at the heart of one of the biggest corruption investigations in the history of sport. They are due to face trial from 13 January 2020 for having been allegedly involved in a scheme in which the Russian athlete Liliya Shobukhova was extorted for money in exchange for hiding anomalies with her biological passport, allowing her to compete at the London 2012 Olympics.

It has already emerged the Qatar organising committee for the world championships, which begin on Friday, sent the IAAF a letter promising to build 10 athletics stadiums around the world the day before the 2014 vote. A second letter, to Lamine Diack only a few hours before the vote purported to promise additional benefits, including a $30m sponsorship from a Qatari bank and the purchase of the TV rights by BeIN for $2.5m.

The IAAF said the 10 stadiums are subject to a “needs-based assessment” to decide where they should go. It said the Qatari bank sponsorship deal was signed last year with all contractual payments going to Dentsu. However a BeIN contract was never signed and BeIN does not hold any rights to the 2019 world championships.

Papa Massata Diack said in an email: “As for Qatar, China, Russia, South Korea, Brazil, UAE, I have full mandate to secure and sign sponsorship agreements, on behalf of Dentsu or [a Swiss company] AMS. Any monies collected by my company is duly documented and approved by my stakeholders: the rights owner. My relationship with Dentsu and AMS does not suffer of any discrepancy. I have helped them enrich the IAAF and the sport of athletics.”

The IOC reiterates its full commitment to the protection of the integrity of sport International Olympic Committee statement

AMS said: “We do not respond to media inquiries.”

The Guardian, Mediapart and Der Spiegel sent a A series of questions to the International Olympic Committee. The IOC reply concluded: “Your requests refer to events before the IOC introduced far-reaching reforms. With the reforms of Olympic Agenda 2020, the IOC reinforced its code of ethics and introduced an approved list of consultants. In order to be on the list, the consultants have to declare they respect the strict IOC rules on governance and ethics, and in particular anti-corruption. Candidate cities can only hire consultants that are on the list.

“The IOC reiterates its full commitment to the protection of the integrity of sport. It will continue to address any issue under the rules and regulations of its recently reformed governance system. The IOC Ethics Commission will continue to monitor the situation and, where evidence is provided, we will act.”

The investigating judges suspect that Papa Massata Diack took commissions on IAAF contracts in exchange for his father influencing the votes for the Rio 2016 and Tokyo 2020 Olympics. In March Tsunekazu Takeda, the chairman of the Japanese Olympic Committee, resigned after coming under investigation by Van Ruymbeke. Takeda has denied any wrongdoing.

Lamine Diack to stand trial for money laundering and corruption Read more

Doha’s unsuccessful bid for the 2017 World Athletics Championships, which was won by London, is also under investigation because of two payments totalling $3.5m which were sent to Papa Massata Diack in October and November 2011 at a time when Qatar was bidding to host several major events, including the 2020 Olympics.

Nasser al-Khelaifi, the president of Paris Saint-Germain and the Qatari media group beIN, and the general manager of beIN, Yousef al-Obaidly, are under investigation by French judges regarding this payment. Both men strenuously deny any wrongdoing.