The city and police are planning a soft roll-out until at least the end of January, with no targeted inspections and only a warning given when the violation is noticed during traffic checks. They later plan to introduce a fine of 80 euros (92 dollars) plus fees and expenses.
Diesel cars that conform to the Euro 4 emissions standards or worse are now banned in parts of the city centre. Residents have until April 1 to switch, and there are exceptions for some professions.
The state of Baden-Wuerttemberg had failed to prevent the ban by taking it to court. The new restrictions affect an estimated 72,000 vehicles in Stuttgart – home to car firms Audi, Porsche and Mercedes-Benz – and surrounding region, a city spokeswoman said.
The Federal Administrative Court in the eastern city of Leipzig decided in February that German cities could impose diesel bans if they wanted to.
The northern port city of Hamburg was the first to impose a partial ban, but it has been widely criticized as ineffective as it covers only two streets and allows for many exceptions.
Baden-Wuerttemberg’s Green Premier Winfried Kretschmann has been under pressure since the Leipzig court decision to introduce a ban.