The Portuguese man was spotted by a passerby who noticed the body trapped in an upper floor window shortly before 10.30am, police said.
The man was in the university’s institute for education building, according to local media reports.
Police and rescue officials arrived on the scene but medics could only note that the victim was dead, police said.
Investigators acknowledged that the circumstances and causes of the man’s death remained unclear.
Experts from the Institute of Legal Medicine at the University of Zurich joined police in the probe.
Police issued an appeal to members of the public who may have relevant information to step forward.
Anyone who was in the vicinity of 35 Beckenhofstrasse between 5pm on Tuesday and 10.20am is asked to contact city police at 0444 117 117.