Federal Supreme Court, 19.09.2025, 1C_79/2024
Facts
C. SA, a co-owner of condominium units in a protected building in Geneva, filed a building permit application in 2017 to create three apartments in the attic.
The Department of Territory issued a permit (11.11.2020), which was confirmed by the TAPI, then partially remanded by the Court of Justice for a recalculation of the maximum sale price.
Following a new decision on January 8, 2024, the A. spouses, co-owners of an apartment on the 6th floor, appealed directly to the Federal Supreme Court, arguing in particular that the condominium association had not given its consent for work affecting common areas (the roof).
Law
Jurisdiction and admissibility
An appeal in public law matters is available (Art. 82 let. a LTF) and the appellants have standing to sue (Art. 89 para. 1 LTF). The issue of condominium consent was definitively settled in the cantonal judgment of August 30, 2022, meaning it can be challenged directly before the Federal Supreme Court (omisso medio appeal) (consid. 1).
Review of civil law in building permit proceedings
Art. 22 LAT implies that a project compliant with public law is, in principle, entitled to a permit. The building permit procedure is intended solely to verify compliance with public law; the civil right to dispose of the property (e.g., condominium consent) is only examined prima facie (consid. 4.2).
Cantons may adopt different practices on this point. An in-depth examination of civil law is not required by the LAT. The Court of Justice noted that the condominium association had not given its consent, but ruled that this is a private law dispute with no effect on the issuance of the permit, provided the project complies with public law. The appellants failed to demonstrate the existence of a Geneva cantonal practice requiring the authority to refuse a permit in the event of a manifest lack of civil right to build, unlike a precedent in Grisons (1C_116/2013) where such cantonal practice was accepted. The issue of the right to dispose of the property may be settled by a civil judge, who can order a halt to construction if necessary (consid. 4.3).
Outcome
The appeal is dismissed to the extent that it is admissible. The court costs of CHF 4,000 are to be borne jointly and severally by the appellants, who must also pay CHF 3,000 in legal fees to C.________ SA.
Silex newsletter published in collaboration with Daniel Hirschi-Duckert, Attorney at Law
