The 87-year-old Senegalese, who led the athletics governing body between 1999 and 2015, was convicted of several corruption charges linked to the Russian doping scandal.
Diack was found guilty of receiving bribes from Russian athletes suspected of doping to conceal test results so they could continue competing, including in the 2012 London Olympics and the 2013 World Championships in Moscow. The court had heard how he solicited 3.45 million euros ($4.1 million) from athletes and paid off other officials to aid with the cover up.
In the trial, prosecutors also alleged that Diack accepted $1.5m payment from Russia to help finance Macky Sall’s 2012 presidential campaign in Senegal, his home country, in exchange for slowing down doping cases involving Russian athletes.
The court handed Diack a four-year prison sentence, two years of which are suspended. But it is not yet clear whether the former International Olympic Committee member will spend any time in prison as he has been under house arrest in Paris for the last two years.
The judge said his actions had “undermined the values of athletics and the fight against doping”.
Diack’s son Papa Massata Diack – who was banned for life from athletics in 2016 – was sentenced to five years in prison and given a 1m euros fine (£913,850) in absentia.
The former marketing consultant at the IAAF did not attend the trial in Paris because Senegal refused to extradite him – saying that the French court had no jurisdiction as the alleged crimes took place in Russia, Qatar, Senegal, Japan and Turkey.
Both men have also been ordered to pay World Athletics 5 million euros in damages for breach of trust.
All four other defendants – Gabriel Dollé, the former head of anti-doping at the IAAF, Lamine Diack’s advisor Habib Cisse, ex-Russian Athletics Federation President Valentin Balakhnichev and Alexei Melnikov, the former the former head distance coach of the Russian national team – were also found guilty of corruption offences.