Key legal question
Whether the tenant's set-off claims for rent reduction were sufficiently substantiated and proved, and whether Art. 8 ZGB was violated by refusing evidence.
Extracted holding
The appeal failed because the tenant did not properly substantiate the challenged factual allegations and did not identify the evidence to be taken; no violation of Art. 8 ZGB was shown.
Extracted reasoning
The Federal Court held that substantiation is governed by federal law, but the appellant's allegations were not adequately supported by record references. Art. 8 ZGB gives a right to evidence only for relevant, properly pleaded facts and within the limits of procedural rules; the appellant did not meet the requirements.