Real Madrid are reportedly taking Benfica's sale of Ezequiel Garay to Zenit Saint Petersburg to the Court of Arbitration for Sport.
Madrid, who sold Garay to the Portuguese champions in 2011, were entitled to 50% of any future sale of the Argentine defender and believe that his sale to Zenit grossly undervalued the player.
Reports in Diario De Noticias suggest that Los Blancos are now aware that Bayern Munich wanted to sign the centre half, whilst at Benfica, and tabled a bid of 15 million euros, which was rejected by the Lisbon club. However, shortly after he was sold to the Russian side for 6 million euros.
Benfica were only entitled to 40% of the Argentine's sale, as 10% of any sell-on fee was sold to the third party Benfica Stars Fund.
The 29-year-old, who had initially moved to the Portuguese capital from Madrid as part of a deal to take Fabio Coentrao to the Bernabeu, joined Valencia last month for 20 million euros.
The trial into the sale was carried out in May, with results expected later this month.
