Act Governing the Allocation of Government Revenues and Expenditures Article 18

No government at any level may impose a double tax or a surtax on the tax levies of another government at the same level or any other level. This restriction does not apply, however, to the governments of special municipalities, counties and county-level cities when, to raise the necessary financing to manage self-government matters, they impose a surtax in accordance with the Act Governing Local Tax Regulations.No local government at any level may impose an entry tax or a transit tax on goods that enter or pass through its jurisdiction.