The lawsuit, filed in San Mateo Superior Court in California, accuses designer Henrik Fisker and Bernhard Koehler, the chief operating officer of Fisker's design company Fisker Coachbuild, of fraud, misappropriation of trade secrets, and breach of contract during their year-long effort in 2007 to style the interior and body of the Tesla sedan, called WhiteStar.
The San Francisco law firm that represents Fisker Coachbuild said it does not comment on pending litigation.
Tesla paid Fisker, who has designed for BMW, Aston Martin and other high-end car makers, nearly $800,000 and gave him access to its trade secrets, business plan and proprietary engineering data developed during production of its first vehicle, the Tesla Roadster, the lawsuit said.
Tesla accuses Fisker of purposely providing substandard designs for the Tesla sedan - resulting in a six-month delay of its release to 2010 - while using Tesla's data and holding back Fisker's best designs for his own vehicle.
Shortly after completing services for Tesla, Fisker and Koehler announced they were forming Fisker Automotive to put out a four-door hybrid-electric sedan called the Karma.
"What he did is outrageous," attorney Adam Belsky of Gross Belsky & Alonso, who represents Tesla, said. "Clearly now in retrospect, Fisker had a strong motivation not to provide his best work for them."
The lawsuit asks a court to bar Fisker from using Tesla trade secrets and confidential information in his car design, and to award Tesla lost profits and punitive damages of an unspecified amount.