This work is in the public domain according to Spanish Royal Act 1/1996, on April 12, about Intellectual Property, article 13,

Legal or regulatory provisions and the drafts thereof, judgements of jurisdictional bodies and acts, resolutions, discussions and rulings of public bodies, and official translations of all such texts, shall not be subject of "intellectual property"

That means that laws, resolutions and so, from the governments, parliaments and other public and official administrations of Spain, its autonomous communities and other public entities, are not eligible for copyright protection.

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As an edict of a government, it is also in the public domain in the United States.

This work is in the public domain in the U.S. because it is an edict of a government, local or foreign. See § 313.6(C)(2) of the Compendium of U.S. Copyright Office Practices, 3rd ed. 2014 (Compendium (Third)). Such documents include "legislative enactments, judicial decisions, administrative rulings, public ordinances, or similar types of official legal materials." These do not include works first published by the United Nations or any of its specialized agencies, or by the Organization of American States. See Compendium (Third) § 313.6(C)(2) and 17 U.S.C. § 104(b)(5).

A non-American governmental edict may still be copyrighted outside the U.S. Similarly, the above U.S. Copyright Office Practice does not prevent U.S. states or localities from holding copyright abroad, depending on foreign copyright laws and regulations.