According to the Czech Republic's law on Copyright, Rights Related to
Copyright and on the Amendment of Certain Laws (Copyright Act):
Law No. 121/2000 of April 7, 2000 Full text
Article 3 Exceptions from copyright protection in the public interest
Protection pursuant to this Act shall not apply to
a) an official work, such as a legal regulation, decision, public charter, publicly accessible register and the collection of its records, and also an official draft of an official work and other preparatory official documentation including the official translation of such work, Chamber of Deputies and Senate publications, a memorial chronicle of a municipality (municipal chronicle), a state symbol and symbol of a regional self-governing unit, and other such works where there is public interest in their exclusion from copyright protection,
b) creations of traditional folk culture, if the real name of the author is not commonly known and if they are not anonymous or pseudonymous works (Art. 7); such works may be used only in a manner which does not depreciate their value,
Therefore this is assumed to be in the public domain worldwide, although some of the above categories may be subject to usage restrictions within the Czech Republic.