Does everyone have to pay Real Estate taxes in Costa Rica?

I have heard that the government is requiring building permits for new construction ($2,-4000) by Foreigners and possibly Nationals too. and a declared value for future real estate taxes.I have heard from a reliable CR national that Nationals never declare Buildings built on their land. I have purchased several parcels of land in CR and when asking the seller for a statement showing all Real estate taxes have been paid to date of sale, was given a statement from the municipality that no tax was due nor ever was paid. Now they want me to start paying real estate taxes on those parcels. Shouldn't the Nationals be subject to the same Laws in a Democracy?