No smoking, no perfume and no mobile phone use - the list of rules at one newly built block of flats in Zurich is so long, it is a wonder anyone chooses to live there.
But for those who do, there is good reason. The 15 apartments have been designed specially for people who claim to have a condition known as "multiple chemical sensitivity".
Sufferers fall ill when exposed to the slightest waft of perfume or whiff of cleaning products.
Most of the residents in the building in the Leimbach area of the Swiss city say they also become weak and sick when near mobile phones or other wireless devices that emit radio waves or electromagnetic radiation.
While few doctors recognise the affliction, The Healthy Life and Living Foundation, which campaigns for greater recognition for MCS sufferers, convinced the Zurich authorities to provide land for the £4.1 million building. Christian Schifferle, 59, the head of the foundation, said he had suffered from MCS since being exposed to toxic fumes in his parents' furniture factory as a child. He has spent most of his adult life camped in a trailer in the pure air of the Swiss Alps. "All my life it has been like I was only half alive," he said.
Mr Schifferle said he realised he was not alone only at the age of 35, when he discovered an American book about MCS. "It makes me weak, anxious, I can't breathe, my lungs hurt, and I get dizzy." Swiss officials say the building is the first of its kind in Europe. They estimate that about 5,000 people suffer from MCS in Switzerland. Many become isolated and say they cannot function in the modern workplace.
A prohibition sign shows the ban of parfum in the newly opened apartment building. Photo / AFP
Lydia Trueb, a spokesman for Zurich housing office, said: "We wanted to help these people to have a calm home where they hopefully will be less sick."
People entering the building are asked to switch off their mobile phones, although they do not work anyway, as the apartments have a built-in shield against electromagnetic radiation which blocks reception. There is no wifi, but there are landlines and internet connections. The few cleaning and personal hygiene products allowed are on display in the lobby.
The block has odourless plaster on the walls, and construction workers were banned from smoking or using aftershave. Even so, Mr Schifferle spends only a few days a week in his flat, as he says he can still smell traces left by the builders.