Abstract This commentary analyses Article 6.1.14 of the UNIDROIT Principles of International Commercial Contracts (PICC) concerning the problem of public permission requirements. According to Art 6.1.14, where the law of a State requires a public permission affecting the validity of the contract or its performance and neither that law nor the circumstances indicate otherwise: if only one party has its place of business in that State, that party shall take the measures necessary to obtain the permission; in any other case the party whose performance requires permission shall take the necessary measures. This commentary discusses the concept of public permission requirements, the nature of obligation to take necessary measures, duty to disclose public permission requirements and to co-operate, legal effects of missing public permission, and burden of proof relating to public permission.