Unfair rent: excessive return or a clearly excessive purchase price

Article 269 of the Code of Obligations treats as unfair a rent that allows the landlord an excessive return on the property, or that results from a manifestly excessive purchase price. Article 269a lists increases that are not as a rule unfair, including those based on changes in costs or in the mortgage reference rate, or that offset additional services. Those criteria do not remove the official form or the 30-day period when an increase is notified during the lease.