Since January 1, only diesel vehicles meeting the Euro 5 emissions standard are allowed into Stuttgart, home of Mercedes-Benz maker Daimler, Volkswagen subsidiary Porsche and the world’s biggest car parts supplier Bosch.
The demonstrators held banners saying “Pro-diesel” and “Diesel drivers mobilise” as they gathered outside a car emissions centre.
“What’s happening to people is unjust,” joint organiser Vasilos Topalis told AFP.
“Tens of thousands of people are affected and can’t afford to buy a new car” following the court-ordered ban, he added.
Environmental organisations last year took to the courts to push through similar driving bans in many German cities where emissions exceed European Union limits.
Judges ordered Berlin, Mainz, Hamburg and Bonn to limit some diesels’ access, while parts of a motorway near Essen will be closed to the cars.