"The appeal lodged by Paris Saint-Germain is rejected. Consequently, the UEFA Control, Ethics and Disciplinary Body's decision of April 25 is confirmed," the European football governing body said on its website.
The UEFA Control, Ethics and Disciplinary Body opened an inquiry into the Brazilian on March 22 over remarks he made on social media following PSG's 3-1 home defeat to United in the second leg of a round-of-16 tie, which eliminated the French club from the competition.
United's victory at Parc des Princes was the result of a controversial penalty call. Going into stoppage time, United led 2-1 on the night, but PSG were still up 3-2 overall.
As the match entered the 95th minute, a shot by United's Diego Dalot bounced off the arm of defender Presnel Kimpembe out of play for a corner.
After reviewing the play with the Video Assistant Referee, the official cited Kimpembe for hand ball and awarded a penalty. Marcus Rashford stepped to the spot and converted to level the aggregate score at 3-3 and give United the edge on away goals.
UEFA penalized Neymar for a social media post following the contest.
"That is a disgrace! And UEFA still pick four guys who know nothing about football to review the VAR decision in slow motion... that handball simply doesn't exist!" Neymar wrote.
( With inputs from IANS )