Hi Intorion,
Do you mean the old german licence plante number? If the car is bought in D the previous owner name should be written in the so called german Fahrzeugbrief. Please check if you still have this document.
If you need some general information about your car you can check it by its VIN. Please type it in the box of the following link: (you can find it also on this page, its called Xedos-infotool)
http://xedos-community.de/infotool.php
Regards,
Street