The agreement reached in August 2014 by Real Madrid and Manchester United on the move of Argentina's Angel di Maria included several clauses to prevent his transfer to another Spanish team, with penalties of 30 to 50 million euros ($33.3 to $55.5 million).
A copy of the agreement with all the details of the transfer was revealed on Friday by the whistle-blowing website Football Leaks whose authors say they are Portuguese but remain anonymous, reports Efe.
Real Madrid agreed to transfer the Argentinian playmaker in exchange for 75 million euros ($83.2 million), divided into three phases of 25 million euros each ($27.7 million), and ends in August 2016.
The document also states that the English side has to pay 5 million euros ($5.5 million) to Real Madrid if Di Maria reached the final list of candidates to win the Ballon d'Or and another 5 million euros if he won the award.
Also included are various provisions aimed at penalising a hypothetical transfer of Di Maria to another Spanish team other than Real Madrid.
In that case, United would have had to pay 50 million euros ($55.5 million) if the Argentine had been transferred to another La Liga club in the summer of 2015; 40 million euros ($44.4 million) from that date until the summer of 2016, and 30 million ($33.3 million) until summer 2017.
In the event that the buyer was Barcelona, the penalty of 30 million euros would be extended to 2019, according to the document revealed on Friday.