PSG hosted Red Star on October 3 for the clubs' second Champions League match in Group C, with the Parisians coming away with a comfortable 6-1 victory.
Earlier on Friday, French sports newspaper L'Equipe wrote on its website that European football's governing body UEFA had alerted French authorities to possible match-fixing in the Oct 3 fixture, based on a tip from a "credible" informant.
However, a report from L'Equipe details allegations UEFA received of match-fixing by Red Star in which a senior member of the Serbian club, with others, meant to place a bet of several million euros on the team to lose by five goals.
Red Star Belgrade issued a statement rejecting the allegation "with the highest anger and abomination".
It was no more than a consolation effort, with Neymar completing the scoring, and his hat-trick, in the 81st minute to give PSG an easy victory. The club categorically rejects any and all direct and indirect implication in relation to these suspicions and would like to point out at no moment has Paris Saint-Germain been approached by the National Financial Court in charge of the investigation. "Red Star expects that the truth about this must come in as short a time as possible and that any doubt about the involvement of any member of our club in any possible disruptive actions must be removed".
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Monaco have yet to comment on the speculation, with vice-president Vadim Vasilyev paying tribute to the departing Jardim. In a club statement , Jardim said: "I'm grateful and proud to have been Monaco coach for more than four years".
"PSG remains at the disposal of the investigators and will not tolerate the slightest attack on its reputation nor that of its officials".
Red Star have dismissed the allegation absolutely.
Having established a 5-goal lead on the night, Thomas Tuchel's men were pegged back to 5-1 when Marko Marin scored with a little under 20 minutes to play. "Current technology is so advanced that it is simply impossible that such a case can not be resolved".
"Uefa only communicates on specific cases/matches once disciplinary proceedings have been opened and/or decisions have been taken".
Brazil global Neymar scored a hat-trick in the game at Parc des Princes, with Edinson Cavani, Angel di Maria and Kylian Mbappe also hitting the target for PSG.