Paris Saint-Germain defender Nuno Mendes was the target of abusive and racist comments on social media after a French league game.
The club condemned the abuse and expressed its "full support" Sunday for the Portugal left-back, who was targeted following PSG's 3-1 win against Brest on Saturday.
Mendes, who is Black, shared on his Instagram account a racist message he received.
During the match, Mendes brought down Ludovic Ajorque in the box for a penalty that Romain Del Castillo converted to give Brest the lead.
"Paris Saint-Germain doesn't tolerate racism, antisemitism or any other form of discrimination," the club said. "The racial insults directed at Nuno Mendes are totally unacceptable ... we are working with the relevant authorities and associations to ensure those responsible are held accountable for their actions."
Portuguese Football Federation president Fernando Gomes has expressed his solidarity.
"It is deplorable that in the 21st century we still have to deal with so many prejudices and racist attitudes," Gomes said in a statement.