Marseille claim to have footage of Neymar racially abusing Japanese right-back Hiroki Sakai during their Ligue 1 win over Paris Saint-Germain earlier this month, a source close to the club said on Tuesday.
The individual said Andre Villas-Boas's side have evidence of the Brazil forward making the comments on two occasions.
A Marseille spokesperson refused to confirm the allegations.
"We have no comment. We entrust all our expertise and analysis to the examiners" of the league, they said.
The world's most expensive player alleged he was the victim of racist abuse by Marseille defender Alvaro Gonzalez in the fixture where five players including Neymar himself were shown red cards.
Last week Brazil's Globo Esporte said PSG had submitted a video of the incident to the French league (LFP) "to attempt to prove that Neymar was the victim of racism".
Three Brazilian lip-reading experts interviewed by Globo TV on Sunday agreed Gonzalez had called Neymar "mono" -- "monkey" in Spanish -- after watching the footage from French broadcaster Telefoot.
However, other lip-reading experts -- notably in Gonzalez's native Spain -- have analysed the same tape and found no evidence the defender used a racial slur.
According to some Spanish media reports, Neymar in fact used a homophobic slur against Gonzalez.
A PSG source told AFP the allegations had "no value".
The LFP, which suspended Neymar for two matches over the incident, has opened a probe into his accusations, which Gonzalez denies.
Later on Wednesday, PSG's Angel Di Maria faces a disciplinary hearing after Gonzalez alleged he was spat at by the Argentina winger during the game.
Television footage appeared to show Di Maria in the act but he avoided punishment by the match referee.
(For more sports news and updates, follow Ahram Online Sports on Twitter at @AO_Sports and on Facebook at AhramOnlineSports.)