A bit late to add information, but I don't think this is important enough to open a new thread.
Easily to find with a searching machine which prefers German language:
Rüdiger Maerz is either authorized support and/or repair center for
Canon
Ricoh
Pentax
Tamron
Tokina
Nissin
Rollei
and some more.
They also have their fingers somehow in the Canon Pro Service (renting and support on site).
Their main business seems to be with Canon anyway.
Ricoh Pentax do list them as their only authorized repair center in Germany.
I personally had never heard about them.
Rüdiger Maerz GmbH
Süderstraße 75a
20097 Hamburg
Germany
Mail
infohamburg@fotomaerz.de
Telefon +49 40 731 40 77
Fax +49 40 732 68 38