Chinese authorities fined Mercedes-Benz 350 million yuan ($56 million) on Thursday for violating anti-monopoly laws and price fixing, investigators said.
"After an investigation, Mercedes-Benz dealers in Jiangsu province were found to have implemented a fixed minimum price for E- and S-class vehicle parts in violation of the anti-monopoly law," said a statement from the Jiangsu province pricing bureau.
Minimum prices were also set for entire E- and S-class cars between January 2013 and July 2014, the statement said.
Three dealerships, in the cities of Nanjing, Wuxi and Suzhou, were separately fined a total of 7.9 million yuan.
The German automaker said it was being investigated in August, but refused to provide more details.
Investigators said price-fixing meetings were organised at some Mercedes dealerships in the eastern province as far back as November 2010.
State media last year said pricing authorities had evidence that Mercedes-Benz controlled prices of its spare parts and maintenance services.
At the time the official Xinhua news agency cited data from the China Automotive Maintenance and Repair Trade Association as showing the total cost of all spare parts for some cars could be 12 times more than a finished model.
It quoted Zhou Gao, head of anti-monopoly department at the price bureau as saying: "The Benz case involves typical vertical price-fixing."
The Jiangsu probe was part of a wider inquiry by China's National Development and Reform Commission (NDRC), one of several government bodies that probes violations of the country's "anti-monopoly" law.
Mercedes-Benz said in early August that it would cut spare parts prices from September in response to the NDRC's actions.
The case comes against a backdrop of sweeping investigations into foreign firms in China in sectors ranging from pharmaceuticals and baby formula to autos.
More than 1,000 companies in the country's auto sector, both domestic and foreign, have been probed by the authorities, the China Daily newspaper has reported.