Generally, when the deceased owned real estate, the value to be considered for the inheritance declaration is the market value on the date of death (Article 761, paragraph 1 of the General Tax Code and BOI-ENR-DMTG-10-40-20 §20). This is the value that would be obtained if the property were sold near the time of death, reduced by a 20% allowance if it was the principal residence of the deceased and the surviving spouse (Article 764 bis of the General Tax Code).
This rule also applies when the property is located abroad (BOI-ENR-DMTG-10-40-10-10 §180).