Facts
On July 2, 2012, A.A. and B.A. filed an application for a building permit to construct four residential chalets of seven apartments each as well as two individual chalets in Ovronnaz (municipality of Leytron), in a low-density tourist residential zone. The project was opposed by the association Helvetia Nostra. On December 21, 2012, the Municipal Council of Leytron granted the building permit and dismissed the oppositions. Helvetia Nostra then appealed to the State Council of the Canton of Valais, which rejected the appeal on June 18, 2014.
Subsequently, on October 30, 2013, the Municipal Council supplemented the building permit with an addendum requiring the use of the dwellings as primary residences. Helvetia Nostra also appealed against this addendum, but the Public Law Court of the Valais Cantonal Tribunal rejected the appeal on February 20, 2015.
Helvetia Nostra then filed a public law appeal with the Federal Tribunal, requesting the annulment of the cantonal judgment and the referral of the case to the municipal authority for a new decision.
Considerations
The Federal Tribunal upheld the appeal and referred the case back to the cantonal court for a new decision. It considered that the almost simultaneous issuance of such a large number of authorizations (45 dwellings in total) in a tourist resort where the demand for primary residences is potentially insufficient could constitute an indication of manifest abuse of rights.
The Federal Tribunal recalled that Article 75b of the Federal Constitution limits secondary residences to a maximum of 20% of the housing stock in each municipality. It emphasized that this provision applies not only to dwellings declared as secondary residences, but also to those that could be used as such.
According to the case law of the Federal Tribunal, a manifest abuse of rights can only be admitted if it is immediately apparent that the project…