UEFA has opened disciplinary proceedings against Paris St Germain President Nasser Al Khelaifi and sporting director Leonardo following Wednesday's 3-1 Champions League defeat by Real Madrid.
Spanish media reported that Al Khelaifi entered the match referee's dressing room shouting after the match, an incident recorded by a Real Madrid employee with a mobile phone.
"We confirm that a disciplinary case has been opened. The UEFA Control, Ethics and Disciplinary Body will take a decision in due course," European soccer's governing body told Reuters.
The French side dominated possession and led 1-0 until Karim Benzema equalised in the 61st minute, a goal PSG coach Mauricio Pochettino felt should have been disallowed because goalkeeper Gianluigi Donnarumma was fouled in the build-up.
PSG, who lost the last-16 tie 3-2 on aggregate, did not immediately respond to a request for comment.