Key legal question
Whether the initial rent could be fixed judicially despite missing official rent-form notification.
Extracted holding
Yes. If the required notification is omitted or defective, the lease is invalid as to rent and the tenant may seek judicial fixation.
Extracted reasoning
Under Art. 270 CO and cantonal implementation, absence or defect of the prescribed notice nullifies the rent clause and allows the judge to set the rent on all relevant circumstances.