Real Madrid have been fined and face the threat of a partial closure of their stadium after a supporter inside the Bernabeu was filmed appearing to perform a Nazi salute.
The incident occurred moments before last month's Champions League game against Benfica.
Real said at the time that the fan had been ejected from the ground after being identified by stadium security, with the club condemning the gesture.
Real were charged by UEFA and have now been fined €15,000 and ordered to close 500 seats in the lower south stand during their next home European match, with that punishment suspended for a year.
Tensions around the match were high, with the second leg coming a week after Real’s Brazilian forward Vinicius Junior had made an allegation of racial abuse against Benfica’s Gianluca Prestianni.
Prestianni missed the second leg after being given a provisional one-match ban, and he could face further punishment pending the result of a full investigation.
Benfica boss Jose Mourinho was heavily criticised for his initial reaction to Vinicius’s allegations, where he cited the way the Brazilian had celebrated his goal, but speaking this week he was unequivocal.
The former Chelsea and Manchester United manager said he was "completely, utterly opposed to any kind of discrimination or prejudice or ignorance or stupidity".
He added: "If my player did not respect these principles, which are mine and Benfica’s as well, then that player’s career with a coach named Jose Mourinho and at a club named Benfica will come to an end."
Real won the second leg 2-1 to claim a 3-1 aggregate victory, with Vinicius scoring the second-half winner. They will face Manchester City in the last 16.
