If you sold your Spanish property between May 2004 and 2006 and you were in those days a non-resident you had to pay CGT AT 35% rate while a Spaniard only paid 15%.
For this reason our Government amends the Law in 2007 and reduced this percentage but you are entitled to claim the refund of this overpayment (20%) by virtue of the non-discrimination tax principle set forth in the UE treaties and because there are many cases ruled by our European Court of Justice (ECJ) in this issue.

fljordan
Spanish Law Firm