The fire broke out shortly after 5 a.m. local time at the complex on Krasnobrodzka Street in the capital's Targówek district, according to the Warsaw Municipal Headquarters of the State Fire Service (PSP).
Fire service spokesman Łukasz Wujek said 45 fire engines and other specialist units, including a hazardous materials response team, aerial platforms and reconnaissance drones, had been dispatched to the scene.
"The source of the fire has not yet been located," Wujek told reporters.
Several vehicles parked outside the dealership also caught fire, he said.
Authorities said no evacuations were required and there were no reports of injuries.
Wujek said firefighting operations were expected to continue for several more hours.
Warsaw police said officers had secured the area around Krasnobrodzka Street and urged residents to follow the instructions of emergency services and avoid the scene.
Traffic on the nearby S8 expressway was not affected, state news agency PAP reported.
The cause of the fire will be investigated after firefighters have extinguished the blaze, police said.
(gs)
Source: TVP Info, IAR/PAP