DUH v. Germany (Building Modernization Act)

On September 28, 2026, Deutsche Umwelthilfe (DUH) filed a constitutional complaint with the Federal Constitutional Court. It challenges provisions of the Building Modernization Act (GModG) and the repeal of sections 71 and 71b–72 of the Building Energy Act. According to DUH, the complaint is supported by young complainants. The complainants allege violations of their freedom as protected intertemporally under the Basic Law, including Article 2(1), and of the state's duty to protect life and physical integrity under Article 2(2), sentence 1, read together with Article 8 of the European Convention on Human Rights.

The Act continues to allow the installation and operation of gas, oil, and liquefied natural gas heating systems in existing and new buildings. The complainants state that the required share of biogenic fuels rises only to 60 percent by 2040, so up to 40 percent fossil fuels remain permissible. They also state that the previously planned ban on operating fossil-fuel heating from 2045 was deleted without replacement, and they contend that the announced green gas quota cannot reliably secure the necessary emission reductions.

Relying on the Federal Constitutional Court's 2021 climate decision, the complainants argue that this shifts necessary emission reductions to future generations and accelerates the use of the remaining carbon budget. Citing calculations by the German Advisory Council on the Environment, they note a remaining budget of 2.5 gigatons of CO₂ for a 1.75°C scenario as of 2025, which could be exhausted by 2033. They further argue that, after the amendment of the Climate Protection Act removed binding sectoral emission targets, the Act fails to give the building sector a sufficiently clear framework for long-lived heating investments. According to DUH, the complaint also raises formal objections: the Act should not have been treated as a law not requiring Federal Council consent, and the Federal President was asked not to sign it but did so.