The German Ministry of the Environment has introduced environmental zones in certain German cities.
All vehicles entering these zones must now display a sticker indicating the Emission class of the vehicle. For vehicles NOT displaying such a sticker, the driver may be subject to a fine of €40.00. This ruling applies to all German licensed vehicles and also to all foreign vehicles that are licensed outside Germany.
Hertz cars outside Germany are not equipped with this sticker. The stickers are available at most gasoline stations at the border.
The restricted zones can be identified by signs which are displayed at the point of entry to a restricted zone.