This is the presentation I have given for the implementation of the 2013 PSI Directive focusing on the issue of Licence Interoperability and the need for a positive Public Domain right for Public Sector Information. It explores interoperability of Open Government Licences with Creative Commons and other standard public licences. I have given this presentation on behalf of the National Documentation Center/ National Hellenic Research Foundation and the Legal Aspects of Public Sector Information 2.0 Network.