CJEU grants EU courts’ jurisdiction to hear foreign patent infringement disputes

On 25 February 2025 the Court of Justice of the European Union (CJEU) delivered a significant decision on the, so-called, long-arm jurisdiction of national courts in cross-border patent infringement cases [1]. The court has interpreted certain aspects of Regulation (EU) No 1215/2012 (aka Brussels I recast), particularly those which relate to the operation of Article 4(1) of the Regulation, which establishes that a defendant should be sued in their country of domicile, including in cases of alleged infringement of a patent elsewhere.

There is an inherent tension between the territorial nature of patent rights, where patents are territorially limited and can only be infringed in the territories of their registration, and situations provided for by Article 4(1) which requires that an alleged infringer be sued in their home country, which might not be the same country where the infringement is occurring (although this appears to be more of a choice for a patentee given Article 7(2) allows for suing in the place of infringement).

In practice, cases of alleged patent infringement almost invariably also involve a challenge to the validity of the patent, which raises the question of what a court which is dealing with infringement of a foreign patent should do about validity. In those cases, Article 24(4) of the Regulation confers exclusive jurisdiction for “proceedings concerned with the registration or validity of patents” to the courts of the Member State where the patent was granted.

Previously, the CJEU’s 2006 decision in GAT v LuK (Case C-4/03), meant that a court seised of non-domestic infringement proceedings concerning a non-domestic patent would be required to defer the issue of infringement to the courts of the territory of registration the moment an invalidity challenge was raised even by way of defence (and even with no challenge to the patent itself in the country of registration). That decision was made in the context of a different convention and the CJEU has had the opportunity to revisit the principles in Electrolux.

In Electrolux the CJEU interpreted Article 24(4) to mean that a court seised of an action for patent infringement by virtue of Article 4(1) (i.e. because it is a court of the defendant’s country of domicile), where that infringement action concerns a patent registered in another EU jurisdiction “does still have jurisdiction to hear that [infringement] action where, in the context of that action, that defendant challenges, as its defence, the validity of that patent, whereas the courts of that other Member State have exclusive jurisdiction to rule on that validity.” That is to say that, while only an EU court of the jurisdiction in which a patent is registered may determine whether that patent is valid for the purposes of upholding it or removing it from the register, that should not prevent a court of another jurisdiction, seised of an infringement action in respect of that patent, from hearing the claim for infringement (without regard to validity).

The mechanism by which it should do so is explained in paragraph 51 of the judgment, such that the court should not make more than a cursory assessment of the merits of the invalidity defence, in deference to the “exclusive jurisdiction” of the courts of the country of registration. If the court “takes the view that there is a reasonable, non-negligible possibility of that patent being declared invalid by the court of that other Member State that has jurisdiction” then it may stay the proceedings, pending a ruling on validity of the other court.

It follows that, a defendant who wishes to raise validity in its defence to an infringement action must be prepared to bring separate proceedings against the validity of the patent in the country of registration, or risk the court seised of the infringement proceedings making a ruling on the infringement claim, without fully considering what would otherwise be a validly brought defence to patent infringement – that there is no valid patent capable of being infringed.

For EU Member States, this approach, seemingly intended to give precedence to the application of Article 4(1) over the inherently territorial application of patents (i.e. so a validity claim cannot defeat infringement jurisdiction by domicile), risks forcing a German-style bifurcated approach to patent proceedings which potentially risks differing patent claim constructions being advanced for infringement and validity. This is something the courts will also have to bear in mind.

In respect of a patent registered in a third country (which would include the United Kingdom), the CJEU confirmed that the Regulation is not applicable and confers no jurisdiction “exclusive or otherwise” on any court of that country. For that reason, the EU Member State court hearing the foreign infringement claim by virtue of Article 4(1) retains the ability to consider the validity of a third country patent in determining infringement, albeit that it would not be a binding decision on the world and would not be “such as to affect the existence or content of that patent in that third State or to cause the national register of that State to be amended” – in other words, that it would take effect purely between the parties.