Article 17.
The provisions of the present Convention cannot in any way derogate from the right belonging to the Government of each country of the Union to permit, to control, or to prohibit, by measures of domestic legislation or police, the circulation, representation, or exhibition of any works or productions in regard to which the competent authority may find it necessary to exercise that right.
Article 18.
The present Convention shall apply to all works which at the moment of its coming into force have not yet fallen into the public domain in the country of origin through the expiration of the term of protection.
If, however, through the expiration of the term of protection which was previously granted, a work has fallen into the public domain of the country where protection is claimed, that work shall not be protected anew in that country.
The application of this principle shall take effect according to the stipulations contained in special Conventions existing, or to be concluded, to that effect between countries of the Union. In the absence of such stipulations, the respective countries shall regulate, each in so far as it is concerned, the manner in which the said principle is to be applied.
The above provisions shall apply equally in case of new accessions to the Union, and also in the event of the term of protection being extended by the application of Article 7.
Article 19.
The provisions of the present Convention shall not prevent a claim being made for the application of any wider provisions which may be made by the legislation of a country of the Union in favour of foreigners in general.
Article 20.
The Governments of the countries of the Union reserve to themselves the right to enter into special arrangements
