I worked several years designing and installing commercial hvac systems in Switzerland. Plenty of offices, banks, museums etc. have ACs. It’s definitely allowed. But you will need a permit to install a fixed system if it affect/changes the building facade.

The reason why most homes don’t have one is that it’s too expensive for the 3-5 days a year you need it. Especially the new minergy houses can keep cool very well even during summer without an AC.