Article 49 of the Decree-Law addresses the tax obligations for a person not registered for tax purposes. It mandates that when such a person imports 'Concerned Goods' from a territory outside the Implementing States, they are required to settle the due tax. The provision specifies that this tax settlement must occur on the exact date of import. The procedural mechanism for this settlement is not detailed within this article but is deferred to the specifications laid out in the Executive Regulation of the Decree-Law, ensuring compliance at the point of entry.