Artikel 6

1. The term “postage stamp” shall be protected under the present Convention and shall be reserved exclusively for stamps which comply with the conditions of this article and of the Regulations.
2. Postage stamps:
2.1 shall be issued and put into circulation solely under the authority of the member country or territory, in conformity with the Acts of the Union;
2.2 are a manifestation of sovereignty and constitute proof of prepayment of the postage corresponding to their intrinsic value when affixed to postal items, in conformity with the Acts of the Union;
2.3 must be in circulation, for postal prepayment or for philatelic purposes, in the member country or territory of issue, according to its national legislation;
2.4 must be accessible to all citizens within the member country or territory of issue.
3. Postage stamps comprise:
3.1 the name of the member country or territory of issue, in roman letters, or, if the International Bureau of the Union is so requested by the member country or territory of issue, the abbreviation or initials officially representing the member country or territory of issue, in accordance with the conditions laid down in the Regulations;5)An exception shall be granted to the United Kingdom of Great Britain and Northern Ireland, the country which invented the postage stamp.
3.2 the face value, expressed: 3.2.1 in principle, in the official currency of the country or territory of issue, or as a letter or symbol;
3.2.2 through other identifying characteristics.
3.2.1 in principle, in the official currency of the country or territory of issue, or as a letter or symbol;
3.2.2 through other identifying characteristics.
4. Emblems of state, official control marks and logos of intergovernmental organizations featuring on postage stamps shall be protected within the meaning of the Paris Convention for the Protection of Industrial Property.
5. The subjects and designs of postage stamps shall:
5.1 be in keeping with the spirit of the Preamble to the Constitution and with decisions taken by the Union’s bodies;
5.2 be closely linked to the cultural identity of the member country or territory, or contribute to the dissemination of culture or to maintaining peace;
5.3 have, when commemorating leading figures or events not native to the member country or territory, a close bearing on the country or territory in question;
5.4 be devoid of political character or of any topic of an offensive nature in respect of a person or a country;
5.5 be of major significance to the member country or territory.
6. Postal prepayment impressions, franking machine impressions and impressions made by a printing press or another printing or stamping process in accordance with the Acts of the Union may be used only with the authorization of the member country or territory.
7. Prior to issuing postage stamps using new materials or technologies, member countries shall provide the International Bureau with the necessary information concerning their compatibility with mail processing machines. The International Bureau shall inform the other member countries and their designated operators accordingly.