unregistered,

As far as I am aware there is no such thing in Spain as a ' Free Transfer ' - even if you were to GIVE your property to a Family member - The transaction would still be classed as a Sale and Tax would become due on the transaction.

As regards the fallen Value of your property - this also would be discounted in the transaction - The Catastral will have the value of your property listed in their records and on it's sale Tax would have to be paid on that value - not on the amount you received for it.

I have recently sold a property for € 200,000 - the buyers had to pay Tax on € 475,000 - because that was it's value according to the Catastral.