Szymon Marciniak will fulfil his role as the referee for the Champions League final after the Pole apologised for participating in an event associated with an extreme-right movement.
European football's governing body UEFA were investigating his presence at an event organised in Katowice on Monday, saying they "abhor the values that are promoted by the group", but kept him on as the referee after an apology and clarification from an anti-discrimination body.
"I want to express my deepest apologies for my involvement and any distress or harm it may have caused," Marciniak said in a statement.
"Upon reflection and further investigation, it has become evident that I was gravely misled and completely unaware of the true nature and affiliations of the event in question.
"I had no knowledge that it was associated a Polish extreme-right movement. Had I been aware of this fact, I would have categorically declined the invitation."
Marciniak, 42, is one of Europe's top referees and also officiated the World Cup final in Qatar when Argentina beat France.
During their investigation, UEFA said they had reached out to 'NEVERAGAIN', an NGO affiliated with the FARE network, which counters discrimination in European football.
"(They) raised the initial concerns about Mr. Marciniak's involvement in the event," UEFA said.
"They requested that Mr. Marciniak remain in his role as the referee for the upcoming UEFA Champions League final, firmly asserting that removing him would undermine the promotion of anti-discrimination."
Manchester City face Inter Milan in the Champions League final at Istanbul's Ataturk Olympic Stadium on June 10.