How do you find such a building ?
I envy you...you really have no worries of any sort that way

In my case, not being in Zurich, but in Bern and planning to move in April when the rent contract ends...I have to find a good place to stay.
I'm also working in Fribourg so I'm looking around Fribourg, Lausanne and whatever else is in the area.
Right now the silence in Bern is driving me to think I'm all alone on planet Switzerland

I live in a first floor (2nd floor if American) flat, in a two story building, ant the end. No upstairs, next door also have a small child which luckily cries more than mine, and downstairs is never there (I am not sure she even exists) and below next door the guy never says anything about the noise.
I'm lucky I guess. I flush the toilet when I want, bathe when I want, and my daughter can stamp and dance and sing when she wants. But I have to be quiet after 8pm wherever I am so it doesn't really matter I guess.