Anyone who is planning on driving to the inner city areas of Berlin, Dortmund, Hannover or Köln needs to have an emission sticker, you can get them at the TüV & some local garages.
The Umweltbundesamt (Federal Office of Environment) have also advised that, effective 01 March 2008, the Decals
will also be required in the following cities:
Ludwigsburg, Mannheim, Reutlingen, Schwaebisch Gmuend, Stuttgart and Tuebingen.
Munich plan to begin as soon as possible but with a start date of no later than 01 October 2008.
Vehicles with a model year of 1993 and newer receive a Green Decal (Emission Category 4).
However, those vehicles with a model year of 1992 and older receive no Decal unless converted to meet the
higher standards. Diesel vehicles have more restrictions.
I don't have a link to this info in English as it came from a work publication, but you can get more info from the ADAC website
Related topic: Munich plans ban on highly pollutive vehicles
Related topic: Emissions stickers for cars driving in Berlin
