The question of the capacity of the parties as well as that concerning the impact of the lack of capability in the contract's validity are excluded from the OHADAC Principles and from other international instruments of unification of contract law [Article 3.1.1 UP; Article 4: 101 PECL; Article I-1:101 (2) (a) DCFR]. They will be regulated by the domestic law which, according to private International rules, is applied to the capacity of persons. Depending on the OHADAC territory concerned, that law will be either the domestic law of the person (under Spanish, French and Dutch traditions) or the law of his domicile (common law tradition territories). Regulation (EC) No. 593/2008 of the European Parliament and the Council of 17 June 2008 on the law applicable to contractual obligations and the Inter-American Convention on the law applicable to international contracts (CIDIP V), held in Mexico on 17 March 1994, exclude the question of capacity from their scope of application [Article 1.2 a) of the Regulation and Article 5 a) of the Convention]. That is why, in Member States, national conflict-of-law rules will have to be applied, subject to the “exception of national interest” provided in Article 13 of the Regulation, which presents a very relative interest in international commercial contracts.