Yes, the regulations depend on the type of building.
The Swiss postal standards state that the letterbox/letterbox system
in the case of a detached house, must be located on a street at the boundary of the property at the entrance to the house. In the case of an apartment building or a commercial building, it must be installed at the entrance to the house, but must not be located behind a locked door.
A well-lit location near the sunnerie is recommended. In the event of any uncertainties or to clarify a specific location, we recommend that you contact your local post office and obtain written confirmation if necessary.