Question juridique clé
Whether the unilateral lease modification introducing separate accessory-cost advances complied with the written-form and motivation requirements.
Solution extraite
The notice was invalid because it did not state with sufficient precision which costs were previously included in the net rent and what effect the separation would have on the rent structure.
Motifs extraits
Art. 269d CO and Art. 19 OBLF require a qualified written notice with precise reasons enabling the tenant to assess the practical and economic impact of the change. General references to categories of accessory costs and a proportional rent reduction were not enough.