Non-discrimination: equal tax treatment required for nationals and enterprises across contracting states, with specified exceptions. Non-discrimination requires that nationals and resident stateless persons of a Contracting State not be subjected in the other State to taxation or connected requirements that are different or more burdensome than those applied to that State's nationals in comparable circumstances. Enterprises and their permanent establishments must be taxed no less favorably than domestic enterprises carrying on the same activities, subject to exceptions for personal allowances and a capped differential in tax rates. Cross-border deductibility of interest, royalties and similar payments is to be permitted on the same terms as domestic payments except where specific exceptions apply; the Article covers taxes of every kind.