Article 64

This Convention affects neither the rights and the undertakings derived from extradition treaties and international multilateral Conventions concerning special matters, nor provisions concerning matters which are dealt with in the present Convention and which are contained in other existing Conventions between Contracting States.

The Contracting States may not conclude bilateral or multilateral agreements with one another on the matters dealt with in this Convention, except in order to supplement its provisions or facilitate application of the principles embodied in it.

Should two or more Contracting States, however, have already established their relations in this matter on the basis of uniform legislation, or instituted a special system of their own, or should they in future do so, they shall be entitled to regulate those relations accordingly, notwithstanding the terms of this Convention.

Contracting States ceasing to apply the terms of this Convention to their mutual relations in this matter shall notify the Secretary General of the Council of Europe to that effect.