Maxeon Solar v Aiko Energy Germany (CFI, 23 August 2024)

Dhenne Avocats · 10 October 2026

Our analysis

Summary

By order of 23 August 2024 (UPC_CFI_336/2024, ACT_36426/2024), the President of the Court of First Instance (F. Butin), after consulting the panel of the Düsseldorf Local Division, granted the request of Aiko Energy Germany, Solarlab Aiko Europe and five other defendants to replace German with English, the language in which EP 3 065 184 on solar cells was granted, in the infringement action brought by Maxeon Solar. Aiko Energy Netherlands supported the request.

Question

Should the language of proceedings change to English where the parties’ interests are evenly balanced and the request was drafted in English?

Decision

The request, drafted in English but accompanied by German translations and not returned by the Registry, is admissible, the Court deciding case by case (Rule 7.1 RoP). On the merits, Maxeon and Aiko being comparable international companies, the defendant’s position is decisive. English is the usual language of solar cell technology. While three defendants are German, the others are based in the Netherlands, Belgium and Italy. Aiko’s main contact does not speak German and Maxeon’s Chief Legal Officer is an English speaker, only the language skills of managers counting, not those of representatives. The change eases coordination among the defendants without harming the claimant, and parallel national proceedings are not decisive. No specific reason justifies departing from the principle that the language of the patent is not unfair to the proprietor. No translation or interpretation arrangements are ordered, none having been requested (Rule 324 RoP).

Key points for practice

• Practical point: where the parties are international groups of comparable size, the defendant’s position and the usual language of the technical field weigh in favour of the language of the patent.

Provisions applied

Agreement on a Unified Patent Court

Arts. 49(1), (2) and (5) and 73(2)(a)

Rules of Procedure

Rules 7.1, 14.4, 220.1(c), 321.1, 323 and 324

Case law cited

The Hague Local Division, 18 October 2023 (UPC_CFI_225/2023), Aarke v SodaStream Industries, Düsseldorf Local Division, 16 January 2024, MED-EL Elektromedizinische Geräte v Advanced Bionics, Mannheim Local Division, 15 April 2024, Curio Bioscience v 10x Genomics, Court of Appeal, 17 April 2024

Prepared by Dhenne Avocats from the official decision, consulted on 10 October 2026. The database is updated every week, on Friday. Only the official text is authoritative.