Police were investigating the causes of the fires which came after a spate of arson attacks against refugee homes amid a record influx of people fleeing war and poverty.
One of the fires destroyed dozens of portable homes and forced the evacuation of 80 refugees, in Rottenburg in the western state of Baden-Wurttemberg, said police.
More than 100 firefighters were called to douse the flames.
Five people suffered injuries when they jumped from windows or had to be treated for smoke inhalation.
Police said they did not rule out arson.