Question juridique clé
Whether the rent increase notice was valid without the landlord's handwritten signature on the prescribed form
Solution extraite
The handwritten signature is part of the required written form for a rent increase notice; a facsimile signature is only sufficient if the exception of Art. 14(2) CO applies, which was not shown here.
Motifs extraits
The statutory form serves identification and attribution. For a unilateral rent change under Art. 269d CO, the form is a qualified written form. Art. 14(2) CO requires established usage of facsimile signatures in the relevant traffic, and no such usage was proven or notorious.