They need to go and get a court order, and with that they request the personal data from the respective ISP. The whole process is pretty steamlined and partly automated though.
Source: have been through many copyright claims and currently have a supreme court lawsuit pending.
Many claims by copyright predators go through the courts in Munich and Koeln which seem to rubberstamp every case. Cunts from Waldorf Frommer being among the most notorius. If only the healthcare, local administration and other services in Germany were working so seamlessly...
Source: have been through many copyright claims and currently have a supreme court lawsuit pending.