Non-discrimination in tax treatment protects nationals, permanent establishments, and controlled enterprises from heavier taxation under the treaty. The non-discrimination rule requires equal tax treatment for nationals of one Contracting State in the other State, and for permanent establishments and controlled enterprises, so that they are not subjected to heavier taxation or connected requirements than comparable domestic or third-State enterprises. The article preserves limited distinctions for personal allowances, reliefs, and reductions linked to civil status or family responsibilities, and defines taxation as taxes covered by the Convention.