Rolf Haferkamp will remain the company's CEO and will lead efforts to restructure the automaker, Wiesmann said.
Wiesmann was founded 25 years ago by brothers Martin and Friedhelm Wiesmann, who developed the first prototype in the cellar of their home.
The company has 110 employees and has sold more than 1,600 of its handmade vehicles with maximum annual sales of about 200 in Europe, the Middle East and Asia.
Problems for niche manufacturers
It's difficult for niche companies to keep up with innovation and economies of scale in the car industry, said Stefan Bratzel, director of the Center of Automotive Management at the University of Applied Sciences in Bergisch Gladbach, Germany.
"Wiesmann may have been hit by declining sales within Europe's car industry," he said. "Often, it's a mix between decreasing sales and rising costs for production and design that drives niche producers into insolvency."
Wiesmann filed for insolvency at the Muenster court in Germany on Aug. 14, the company said.