What are the Area Control Center (ACC) frequencies for Germany?
The radio frequencies used by German ACC sectors are listed in AIP Germany ENR 2.1 (page 36 onward). This is the standard place to find ACC frequencies for any country in the world.

There are too many frequencies to list here, but you can find the full document here. Below is a screenshot of page 36. Column 1 contains the sector name and dimension, column 4 contains the frequency(ies) used by that sector.