The match also witnessed three red cards in stoppage time, with Milan being reduced to nine men as tensions flared
The France forward switched from Atletico to Barca in July after the Catalans exercised his release clause, although Atletico complained that negotiations took place when Griezmann was under contract with them.
The RFEF's competition committee said in a statement on Thursday that Barca broke its rules by beginning negotiations with Griezmann while he was under contract with Atletico without their permission, but absolved the player of any responsibility.
Barca and Atletico were not immediately available for comment.