Busquets faces UEFA disciplinary hearing
"UEFA has opened disciplinary proceedings against Barcelona midfielder Sergio Busquets, who is alleged to have violated... the UEFA disciplinary regulations by directing racist abuse towards a Real Madrid player," UEFA said in a statement.
"The proceedings have been launched on the basis of evidence provided by Real Madrid (video and statement of club and player)."
UEFA said the alleged offence happened during the first leg of the tie at the Bernabeu on April 27.
Barcelona won 2-0 and following a 1-1 draw in the second leg they reached the May 28 final against Manchester United at Wembley.
UEFA said Spanish international Busquets had allegedly violated article 11 of its disciplinary code.
This reads: "Anyone who insults the human dignity of a person or group of persons, by whatever means, including on grounds of colour, race, religion or ethnic origin, shall incur a suspension for five matches or for a specified period."