Court of Cassation: Right to Elevate Buildings Belongs to Co-owner Syndicate

When the third civil chamber of the Court of Cassation ruled on April 2, 2026, it settled a recurring dispute over apartment building expansions by declaring that the right to build upward belongs exclusively to the syndicate of co-owners rather than the top-floor resident, absent a clause in the building’s bylaws. This decision, detailed in the case file for pourvoi n° 24-15.059, sets a clear legal baseline for property developments across France.

Key Takeaways:
• The right to construct upward to create new private spaces belongs to the co-ownership syndicate by default under the law of July 10, 1965.
• Owners of top-floor units hold no automatic prerogative over the airspace above their ceilings, meaning any preliminary sales promise regarding a right to elevate requires careful documentation review.
• Building expansions intended to create private rooms require a reinforced majority vote under Article 26, representing at least two-thirds of the votes of all co-owners.

The Third Chamber Ruling of April 2, 2026

The legal framework governing building extensions stems directly from the classification of the airspace as an accessory to common parts. The April 2, 2026 ruling reinforces that the syndicate alone holds the power to authorize such projects or sell the rights to a developer during a general assembly. Top-floor occupants frequently experience the direct impacts of construction or harbor ambitions to expand their own living space upward, yet the law grants them no inherent ownership of the volume above their roof.

Prospective buyers looking at top-floor units often rely on informal promises or poorly drafted real estate listings. However, the absence of an explicit clause in the co-ownership bylaws routing the expansion right to a specific lot leaves the power entirely with the collective syndicate. Practitioners note that real estate operators and property holding companies buying single-lot top units in complex buildings must verify these bylaws well in advance of any financial commitment.

Historical Precedents and Transitory Rules in Paris

While default rules favor the collective syndicate, historical exceptions exist under strict statutory conditions. A judgment from the Judicial Tribunal of Paris on February 10, 2026 (n° 22/04428) examined a set of bylaws that explicitly attributed a right to elevate to four specific lots. The tribunal scrutinized these clauses under the former Article 37 of the 1965 law, which mandated that any convention post-dating the legislation must explicitly detail the scope, scale, and exact impact on co-owners’ charges and rights.

Rooftop Expansions Require Reinforced Majority Votes

Executing a rooftop expansion demands rigorous adherence to voting thresholds defined by statute. Article 35 of the July 10, 1965 law dictates that creating new private premises via structural elevation requires a vote under Article 26, which demands approval from members representing at least two-thirds of all votes. When the syndicate decides to sell this expansion right, the law requires both this reinforced majority and a confirmatory vote from a special assembly composed specifically of the co-owners whose lots lie within the targeted building.

To protect residents directly underneath the proposed construction, the statute grants them a priority purchasing right when the syndicate sells the newly created private units or the expansion right itself. The managing agent must notify affected residents, opening a two-month window where this purchase priority remains active.

Sanctions and Procedural Risks of Unauthorized Works

Bypassing the collective voting process or initiating construction without proper authorization exposes project holders to severe legal vulnerability. Pushing forward with physical changes without clear authorization can transform a manageable legal dispute into a total patrimonial loss, as courts may order complete demolition under financial penalties.

Contesting a general assembly resolution requires swift legal action. Once a window for challenge closes, the resolution achieves legal finality. Courts have consistently upheld that once an authorization becomes definitive, co-owners cannot later invalidate the underlying decisions, leaving affected parties with limited recourse if they fail to act within the statutory timeline.

The question of whether future legislative adjustments might create an autonomous sub-regime of property rights for special common parts remains open, as current statutes continue to vest ultimate authority in the principal syndicate.

Disclaimer: The information provided in this article is for educational and scientific communication purposes only.