Usually, all people resident in Belgium have to pay personal income tax (IPP) in Belgium.
"However, due to an agreement between the European Union and Belgium, some civil servants, important figures and other persons working for the European Union, the Court of Justice and the European Investment Bank (EIB) are presumed to have maintained their fiscal home in the country they lived in when they took office. This measure, usually called ""exception de domicile fiscal"", means that the state considers these people as not living in the realm - even if they have established residence in Belgium - and they are therefore required to pay tax as non-residents, rather than IPP. The people who can claim the « exception de domicile fiscal » once they start work are the civil servants, important figures and agents already mentioned above who have come to live in Belgium solely because they were employed by the European Union or other institutions concerned and who, when they took office, were fiscally resident in another member state. The partner and any dependent children who are the responsibility of an EU civil servant benefiting from the « exception de domicile fiscal » can also be considered as non-resident in the country if they had their fiscal home in another member state other than Belgium when the civil servant concerned took up office. For the partner, the requirement is also that they must not practice their own professional activity. The EU civil servant who has other professional activities in Belgium as well as being employed by the EU normally loses the right to benefit from this exemption. Nonetheless, revoking this right cannot be justified when the professional activity is clearly on top of the other functions, for when this is the case one could still argue that the person needs to live in Belgium merely because of the functions he/she person occupies within the EU institutions. The agreements that Belgium has signed with the other EU Member states to prevent double taxation aim to define which country can tax income obtained in one of the signing states by a resident from another state. For example, the agreements state that tax on revenue from property situated in Belgium must be paid here. Lastly, EU civil servants must make sure they pay regional taxes (TV licence, refuse taxes, and so on)."