Good news:
The official Mageia forum for the German speaking community is open for the public!
For the moment the automatic redirection is not in place yet, you have to give the full address to your browser:
https://forums.mageia.org/de/ (pls do not forget the trailing slash!)
To log in use your login data as given in http://identity.mageia.org
On behalf of the German admins: Have fun!