How is this possible? Spain came under the spotlight after a Madrid court ruled that an English couple were unlawfully charged 20% more in capital gains tax when they sold their property in 2004. ... Before 2007 the local Spaniard paid 15% in capital gains tax whereas foreign property owners paid 35% - a whopping difference! Since 2007 a flat rate of 18% has been levied on all property owners.
Although I wouldn't go jumping for joy yet as I doubt the Spanish government are going to take all of this with a pinch of salt. If future claims are successful they stand to lose a lot of cash!
However if you think you maybe due a refund you better act fast as under Spanish law you can only claim back tax on the last four years!