In a landmark decision dated March 20, 2026, the Unified Patent Court (UPC) allowed a change in the language of proceedings in the case of HyGear v. Topsoe from German to English. The decision by Florence Butin, President of the UPC Court of First Instance, clarifies the balance between the principle of fairness, the interests of defendants, and the specifics of expedited procedures, setting an important precedent for transnational patent disputes before the UPC.
The case concerned European patent EP3802413, which protects steam methane reforming technology for hydrogen production and is owned by the Danish company Topsoe A/S (formerly Haldor Topsøe). In December 2025, Topsoe applied to the Düsseldorf Local Division for an order to inspect and preserve evidence against four defendants: HyGear B.V. (Netherlands), SYPOX GmbH (Germany), Josef Kerner Energiewirtschafts GmbH (Germany), and the Technical University of Munich (TUM). The proceedings were initially conducted in German—the official language of the Member State where the division is located, in accordance with Art. 49(1) UPCA.
Following the appointment of representatives on January 12, 2026, HyGear filed a motion with the President of the Court of First Instance on January 15 to change the language to English—the language in which patent EP3802413 was granted. Legally, the motion was based on Art. 49(5) UPCA in conjunction with Rule 323 RoP, which allows the President to designate the language of proceedings on grounds of fairness, particularly taking into account the position of the defendant.
HyGear justified the motion by stating that the company does not operate in German, and that conducting the process in this language would cause significant costs and delays, whereas Topsoe uses English in its operations and a significant portion of the submitted documents was in English. The technical field—hydrogen technology—primarily operates in English, and the expedited nature of the proceedings makes language barriers even more critical. The other defendants, with the exception of the Technical University of Munich, did not object.
Article 49 UPCA defines the official language of the Member State as the default language but provides for changes by mutual agreement of the parties (Art. 49(3) and 49(4)) or upon the application of one party based on a fairness assessment (Art. 49(5)). UPC case law includes a multi-factor approach to assessment, considering technical language, the language of documents, the nationality and internal working language of the parties, the ability to coordinate actions between defendants, and the expedited nature of the proceedings. When the balance of interests is equal, the position of the defendant is decisive.
In the decision of March 20, 2026, President Butin granted the change of language to English. The conclusion was based on the following grounds: hydrogen technology is an international field where English is the lingua franca; a significant portion of the documents is already in English; in expedited proceedings, the language barrier creates a substantial disadvantage for the defendant regarding costs and reaction speed; the balance of interests was generally equal, making the defendant’s position decisive; and TUM’s objection was insufficiently substantiated.
The practical implications of this decision for the UPC include the strategic importance of choosing the language of proceedings, especially in multilateral and expedited cases. Key takeaways: motions under Art. 49(5) should preferably be filed before the submission of the defense; the presence of multiple defendants with a common English internal language strengthens the position; and the language barrier in expedited proceedings increases the chances of success. An objecting party must prove a specific and significant disadvantage to themselves.
Decision UPC_CFI_1849/2025 demonstrates that the UPC conducts a genuine assessment of fairness when choosing the language of proceedings, and the position of the defendant can be decisive when the interests of the parties are balanced. This is particularly relevant for international defendant companies operating in a working language other than that of the local division. Patent EP3802413 also remains the subject of parallel proceedings, including a revocation action filed by SYPOX GmbH in March 2026 (UPC_CFI_894/2026).
Founder of Research & Patent group Intectica, author of patent algorithms for solving problems in the pharmaceutical industry, patent attorney certified in all intellectual property objects (Patents, Design, TM), with education in chemistry and law, chief expert of the patent institution of Ukraine UKRPATENT (1997-2004). Member of international organizations, including ECTA, PTMG, UAM, lecturer and blogger.
