The European Court of Justice has struck down the European Commission's decision to approve state aid from Hungary for the construction of the Paks II nuclear power plant in Hungary, arguing that it was unclear whether the Hungarian government had followed EU procurement rules when awarding the contract to the Russian state-owned nuclear corporation Rosatom without a public tender procedure.

The Court ruled in September 2025 that the European Commission should have taken into consideration EU public procurement rules when it approved Budapest’s plans to subsidise the construction of two new nuclear reactors built by Rosatom at the existing Paks nuclear power station site, about 120 km south of Budapest. The original 2017 decision by the commission to approve the investment aid had been contested by Austria, which has traditionally been anti-nuclear power.

Hungary’s government has announced that it would continue the project as planned, but was ready to cooperate with the European Commission to demonstrate it had met public procurement and state aid requirements. In December 2024 the Hungarian nuclear regulator approved a preliminary safety report for the project, known as Paks II (2.4 GW), paving the way for the pouring of first concrete.