Byton, backed by Chinese retailer Suning among others, was facing trouble funding its planned expansion in the Chinese market, causing tensions inside the company and prompting the decision, Manager Magazin said.
It cited a spokesman for Byton as saying that the company saw no reason for such speculation.
Sources told Reuters in January that Byton was seeking to raise at least $500 million euros to finance its growth plan, and Breitfeld told a German magazine in October that it might launch an initial public offering.
Manager Magazin said Breitfeld would leave before Byton's first premium SUV model, M-Byte, enters mass production this year, Manager Magazin said.
Breitfeld, a former BMW top executive, co-founded Byton in 2016 and acted as CEO until the startup overhauled its leadership structure in January, naming Breitfeld chairman and appointing Daniel Kirchert, a former Dongfeng Infiniti executive, as CEO.
(Reporting by Tassilo Hummel; editing by John Stonestreet)