Berlin environmental zone

Since January 1, 2008 Berlin's inner city is an 'environmental zone' where only cars that are up to emission standards are allowed. Vehicles with extremely high emissions of noxious substances are banned from the inner city. The environmental zone is the area within the suburban rail ring. You need a sticker with information about the emission standard of your car. You can get these stickers in authorized garages.
More information is given here...