Question juridique clé
Whether the 31 October 2003 rent-change notice was binding despite the landlord's drafting mistake.
Solution extraite
No. The tenant could not, in good faith, understand the notice as a rent reduction; the notice was therefore not binding in the asserted sense.
Motifs extraits
Interpretation under the trust principle comes before any mistake analysis. Here the stated figures and context showed only an increase of CHF 22 for the parquet floor, not a reduction of the initial rent. The tenant should have had doubts and asked for clarification.