One of the injured was airlifted out of the Hesse city's Werries neighbourhood to a hospital in Dortmund.
The shooting began during a group breakfast for seniors, according to the local newspaper. A single gunman opened fire on the group, killing one.
The shooter is then reported to have shot himself.
Police are reporting there is no further danger to those in the area and have let residents back into their home. The motive for the attack is not yet known.
Homicide investigators from Dortmund are on their way to the scene.
Updates to follow...