The collapse occurred at around 3:30 am Saturday morning, on the corner of Josefstädterstraße and Blindengasse.
The roof and top floor of an adjacent apartment building were damaged. A total of 15 people were evacuated as a precaution, but fortunately no-one was injured.
On Saturday morning, police and fire crews were securing the scene, and have blocked roads until further notice.
Photo: APA/Herbert Neubauer