UEFA is investigating Juventus fans who traveled to Parc des Princes for Tuesday's Champions League game and allegedly participated in racist and antisemitic behavior.
Four people were also arrested.
According to Reuters, social media footage appeared to show some Juventus fans "making Nazi salutes and monkey gestures" during Paris Saint-Germain's 2-1 victory.
"In accordance with Article 31(4) of the UEFA Disciplinary Regulations, a UEFA Ethics and Disciplinary Inspector has been appointed to conduct a disciplinary investigation regarding allegations of discriminatory behaviour by Juventus supporters," UEFA said in a statement.
As for the arrests, Paris police released a statement saying, "Four individuals were identified by video and then arrested last night [Tuesday] by the police for public incitement to racial hatred in a sports venue, on the occasion of the PSG-Juve soccer match."
On the field, Paris Saint-Germain captured the Group H opener thanks in large part to individual brilliance by Kylian Mbappe.
The 23-year-old star scored two goals in the first half, which held up despite a second-half goal from Weston McKennie on the other side.
Paris Saint-Germain will face Maccabi Haifa in the UEFA Champions League on Sept. 14, while Juventus plays Benfica on the same date. Benfica leads Group H after one game thanks to its 2-0 victory over Maccabi Haifa.