Have a look around the car park for a small sign (Paper A3 size) mounted at eye level or higher or lower. Usually they are made from aluminium and explain that a judge has decided a fixed penalty can be made for people parking incorrectly.
If there is a sign, then:
- Pay the bill. Money goes into landlords account.
- Do not pay the bill and wait for court verdict. Money goes into community chest, will be most likely more than CHF 50 expect at least CHF 150 with all court feese. (As it is not a normal simple traffic fine, only the actual driver of the car can be fined)
If there is no sign:
- Do not do anything. No contact. Nothing. Zipp. Nada.