1. Getting a driving licence in Germany
If you do not have a driving licence but want to drive a car in Germany, then you have to go to a German driving school, "Fahrschule". You can, however, take the theoritical part in your mother language.
2. If you already have a driving licence from your home country
If you have a valid driving licence issued in a European country, then you can safely drive in Germany. If you do not have a European driving licence, then you need to exchange your non-EU driving licence within 6 months of moving.
Please visit Europa.eu for details.