Are you looking to buy or sell property in Brussels? Non-Belgian EU citizens owning property in Brussels have the same fiscal obligations as those living anywhere else in Belgium.
The only difference is that some taxes are managed by the Brussels regional public services. All fiscal competencies of Brussels Taxation, the regional tax department, can be found here: https://fiscaliteit.brussels/nl/landingspagina/belastingen-en-heffingen
All information on your property-related fiscal obligations in Belgium can be found here: https://financien.belgium.be/nl/particulieren/woning
In English, you can find information on Belgian property taxes here: https://www.commissioner.brussels/i-am-an-expat/taxes