Ok, you don't want to learn something here. The German law knows the Urheberrecht and the rights of use, i.e. distribution rights. So, this denies automatically the existence of any PD here, which would mean the copyright ended or it was never existent.
Sure somebody can declare his work as free downloadable or free distributable. But you don't have the permission for all the scene demos on the CD's, that's for sure.