The roof of the building in the town of Wesel, in the state of North Rhine-Westphalia, caught fire after the microlight plane crashed into it, a police spokesperson said.
Witnesses told local media they saw the plane colliding with a hot air balloon shortly before the crash, which also injured a child.
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The victims have yet to be identified, according to local media. It is not known if the pilot is one of them.
The injured child is believed to be living in one of the building’s five apartments, the spokesperson said.
The ULM plane had a maximum capacity of two people.
Emergency workers found a parachute near the site, believed to be the plane’s emergency braking system.
The fire is under control and the site has been cordoned off. Firefighters and police remain at the scene of the incident.
The spokesperson said the plane likely took off from Marl Airfield.
The town of Wesel is approximately 65 kilometers (40 miles) north of Düsseldorf.