A quick search with ProjFinder reveals that your coordinate reference system might be one of these :
EPSG:3835 Name:Pulkovo 1942(83) / Gauss-Kruger zone 3
EPSG:3333 Name:Pulkovo 1942(58) / Gauss-Kruger zone 3
Which correspond to a point located just south of Ludwigsfelde, near 52°15'58.7"N, 13°15'41.3"E:
Without more information, it is hard to tell which ...
If you have proj 6 installed, you can query the proj.db file to get the list of EPSG codes it supports. On my machine, the following works:
sqlite3 /usr/share/proj/proj.db "SELECT code FROM projected_crs WHERE auth_name = 'EPSG';"