This is a developing story and will be updated as more information arises on this sensitive incident.
Istanbul Basaksehir left the pitch at the Parc des Princes and Paris Saint-Germain joined them following allegations of racism made against the fourth official in France.
UEFA is conducting an investigation and the match will be played on Wednesday with changes to the referee crew.
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The BBC reports that the official made a racially-charged comment when sending off Basaksehir assistant Pierre Webo.
PSG confirmed that the incident involved the referees and included “racist remarks” from the fourth official.
Basaksehir’s Demba Ba led the walk-off, with reports saying that the fourth official used the term “negro” to identify Webo when the head referee asked which assistant should be sent off.
Demba Ba immediately after: "You never say: "This white guy." Why when you mention a black guy, you have to say this black guy."
— Get French Football News (@GFFN) December 8, 2020
One of the officials responds that it is a miscommunication relating to "Romanian language."
The Turkish visitors had already been eliminated but Thomas Tuchel’s PSG were not through to the knockout rounds and needed a win or a draw and help from RB Leipzig (the latter of which they received).
Reports out of France say that the fourth official was alleged to have said something racially offensive to a Basaksehir assistant coach.
Both sides addressed the officials in a slow down after about a dozen minutes that lasted more than 10 minutes before both sides left the pitch.
Besides the ugly nature of the incident, there’s the matter of advancement from the UCL but PSG holds the tiebreaker over Manchester United, who lost 3-2 to RB Leipzig.