Paul Pogba and Raphael Varane were both involved in a row following France being knocked out of the Euros by Switzerland.
A group of France stars were seen arguing on the pitch during the match and things got worse after the defeat as the World champions were dumped out of the competition.
Pogba helped put France 3-1 ahead 25 minutes before the end in the last-16 clash.
But some of his teammates were reportedly unhappy with the lack of defending he was doing on the night.
Bayern Munich defender Benjamin Pavard is said to have voiced his concerns about Pogba's reluctance to get back and help out, but crucially, the Manchester United midfielder heard this via Varane.
"Benj (Pavard) thinks that you are not defending enough," Varane is said to have told Pogba, according to Le Parisien.
A furious Pogba is then said to have confronted Pavard to ask: "What did you say?"
Pavard alleged continued with several insults as the row escalated.
Tensions between a number of players are said to still be at boiling point, which is potentially bad news for Man United, who are looking to partner Varane with Pogba in the coming season.
Although, the report claims Pogba later apologised to Varane.
The Red Devils have made signing a centre-back a priority this summer and Varane is at the front of Ole Gunnar Solskjaer's wishlist.
Varane is out of contract at Real Madrid next summer and has no current plans to pen a new deal with the Spanish giants.
Real Madrid are reluctant to sell, but they may be left with little choice if they don't want to lose the defender on a free at the end of next season.
Manchester United recently agreed on a deal with young England international Jadon Sancho.
The £72.9million transfer is expected to take place after the Euros.
