City council on Monday approved the installation of the boxes, meant to be places where prostitutes can take customers and conduct their business discreetly, in the Alststetten area.
The boxes, which are used in various German cities, are covered, garage-like structures wide enough for a car to be parked.
Approved by city voters in March after discussions for a couple of years, plans call for them to be operational in August, with construction starting in May at a cost of around 2.4 million francs.
At the same time the city will be closing off to the sex trade areas, such as the Sihiquai, where open prostitution has become a social problem, often involving crime, violence and disruption for residents.
The city is providing social and health care services and maintaining a road barrier on the Zahringerstrasse as part of its package of measures to control the sex trade.
Prostitution is legal in Switzerland but managing red light districts has proved to be a challenge in Zurich and other cities.
The country’s largest city is introducing licencing requirements in January for street prostitutes and for those plying their trade in “salons”.