The former Liverpool and Crystal Palace defender has played just 40 minutes of action this season in the final year of his contract, and tensions have risen over manager Michel Der Zakarian phasing him out.
L'Equipe, via GetFootballNewsFrance, report that a Tuesday night training session spiralled out of control when Der Zakarian didn't award the 33-year-old a free-kick and he stormed back to the dressing room.
The head coach then decided to make an example of the former Paris Saint-Germain man, who was keen to point out his professionalism and lack of complaints despite playing just seven minutes in Ligue 1 this season.
A derogatory comment from Der Zakarian saw Sakho respond by grabbing him by the collar, falling to the floor and breaking a family heirloom necklace.
A Ligue 1 insider corroborated the report, and added that the comment that provoked Sakho was being called a 'cry-baby'.
READ MORE ON FRENCH FOOTBALL
Newcastle hero Dan Burn reveals which three surprising shirts he has collected
Andy Carroll scores 40-yard wonder goal for Amiens as French adventure continues
Der Zakarian refused to comment on the situation when asked, and it's further been reported that Sakho's contract could be terminated early.
The former France international had a similar fall from grace that ended his four-year stay at Liverpool in 2017, but disagreements between him and Jurgen Klopp over punctuality were similarly left to media speculation.
Despite his struggles at Anfield, where he'd been a regular under Brendan Rodgers, Sakho went on to star for south London side Palace, helping Roy Hodgson's side maintain their Premier League status.