As far as I know wild camping is not allowed.

I found a note on the TCS website,here it is roughly translated apologies for my pidgin english.:-D

If wild camping is allowed or not depends on the local cantonal or town laws.
It's generally forbidden throughout Switzerland along shores of lakes as well as rivers.In some cantons,for example Graubünden and Ticino it is generally forbidden to camp e.g put up a tent or station a caravan outside of a specially designated area,elsewhere you need to ask the permission of either the owner of the land or the local police.

I will keep on looking and post if i find a legal based text.