The colours of external architecture are crucial to the reception of urbanized space. An appropriate concept is necessary to maintain order and harmony of colours. Decision-making in this respect was analysed, based on Polish and Slovak legal acts. The formal and actual status was compared through analyses of local spatial development plans and site inspections. For a broader perspective, examples from some of the countries are presented. Using a survey, public knowledge of the current legal situation related to colour decision-making was investigated alongside preferences as to who should manage this issue. It was also investigated how space users assessed the external colours of buildings in the areas under study.