Key legal question
Whether four comparable rents suffice to prove local or neighborhood usual rent under Art. 269a lit. a CO.
Extracted holding
In principle, at least five comparable cases are required to draw sufficiently reliable conclusions; absent exceptional circumstances, four comparables do not establish the usual rent.
Extracted reasoning
The Court reaffirmed settled case law that five comparables are generally needed, each broadly matching the disputed apartment in location, size, equipment, condition, and year of construction. The rule is strict unless exceptional circumstances are shown.