A non-smoking apartment block has been built in Zurich, the first of its kind in Switzerland. (RTS/swissinfo.ch)

All 40 apartments in the block, built by the Schönheim housing cooperative, have been sold. Tenants sign a contract agreeing not to smoke, while their guests are also banned from lighting up. If they break the rules, they can be evicted. Meanwhile, other specialised housing units are emerging in the city: including one for carless owners. 

Not everybody likes the idea. Tenants associations such as ASLOCA are up in arms, saying that it is an intrusion into people's private affairs to impose a non-smoking policy, and that it opens the door to all types of discrimination. 

Patrick Rérat, from the urban geography department at the University of Lausanne, disagrees. He thinks there's plenty of room in such a saturated market to provide special types of living space for niche clients.