First of all, if the language is german, it belongs somewhere under http://www.dmoz.org/World/Deutsch. From there on oit dependa of the type of site. If it's an online shop, it should be under http://www.dmoz.org/World/Deutsch/Online-Shops. From there on, we differ by the kind of items the shop sells. I think you can figure the correct subcategory out for yourself whern looking into the alphabar in the given category.
Additionally, if a physical shop exists where you can walk in, or the shop is of some other high regional relevance, a second listing can be placed in the Regional part. Which in this case would be somewhere in http://www.dmoz.org/World/Deutsch/Regional/Europa/Deutschland/Berlin/Wirtschaft/ .
If for some reason an additional english language version of the site exists, the links "English" in the abovementioned categories point to the english language version of the categories.
BTW: We do have a german language sectionof this forum avaibale if you prefer to ask further questions in german.