I mixed it up again. http://www.fugawi.de/TeleAtlas-Karten-Deutschland.html states that the data is in GDF format, of which the format is available. Also, it says that it is usable for GIS, for which a specification seems to be available at www.opengis.org.

Well, I am doing research here without really knowing what is needed, but it seems that the data format on the CD is a stanrdard format.

Till