People were reportedly given first aid at the scene and transported to hospitals, as emergency medics responded to the incident. One woman is also said to be suffering from shock.
According to Bild, "at least 10" shots were allegedly fired, and a "fired cartridge case" was discovered on the scene.
The shooter is reportedly still at large.
"Heavily armed forces" have cordoned off the area near a bar on Müllerstrasse, and the homicide squad has launched an investigation into the incident.
No further details are immediately available.