This is correct. For example, German law is based on the concept of 'Urheberrecht', ie 'creator's rights', instead of 'copyright'.
This is the reason why copyright notices (which were mandatory in the US until 1989 according to Wikipedia) were never necessary in Germany and why there's no direct equivalent to public domain:
As soon as you create something worthwhile, you gain creator's rights, and as you remain the creator no matter what you do or what usage rights you grant to others, you can't give them away completely. There's a somewhat recent, rather embarrassing quote by German politician and lawyer Volker Kauder, who claimed to have acquired creator's rights to some images he used on his homepage without having the appropriate usage rights.
This is the reason why copyright notices (which were mandatory in the US until 1989 according to Wikipedia) were never necessary in Germany and why there's no direct equivalent to public domain:
As soon as you create something worthwhile, you gain creator's rights, and as you remain the creator no matter what you do or what usage rights you grant to others, you can't give them away completely. There's a somewhat recent, rather embarrassing quote by German politician and lawyer Volker Kauder, who claimed to have acquired creator's rights to some images he used on his homepage without having the appropriate usage rights.
Anyway, you need an explicit license like http://pdclib.rootdirectory.de/wiki/License or http://creativecommons.org/publicdomain/zero/1.0/ if you're German and want to add code to the 'public domain'.