Two Turkish men, aged 33 and 41, were injured in the shootout at a property at 37 Brauerstrasse shortly after 3pm, city police said.
The two men were taken to hospital for treatment of gunshot wounds but their lives are “out of danger”, city police spokesman Marco Cortesi told the SDA news agency.
One of the men underwent an emergency operation, the SDA said.
The shooter fled the scene.
Police said the circumstances and the motives behind the shooting were not immediately known.
The site of the shooting, close to the Langstrasse, is a business called Perla-Mode described by the SDA news service as a cultural space.
The victims of the shooting did not live in the building.
Police evacuated four people not linked to the attack from the building.
Forensic officers scoured the building looking for evidence.
City police issued a call for witnesses who may have seem suspicious activities in the neighbourhod to phone 044 247 22 11.
Cantonal police meanwhile are looking for gunmen who stole at least 30,000 francs’ worth of electronic equipment from a school in Rümlang, north of Zurich, earlier in the day.
The thieves searched a total of 19 rooms, including the teachers’ room and the library, and left a “trail of destruction”, damaging doors, closets and drawers, police said.
The broke a window to gain access to the school.
Stolen items included several expensive cameras, around a dozen computers and cash.
Police estimated total damage at 40,000 francs.
Classes of 300 students were disrupted on Thursday morning while police conducted an investigation at the school.