Barely two years after its operational launch, the Unified Patent Court (UPC) has already begun shaping a transnational doctrine of patent infringement by equivalence.
Between late 2024 and mid-2025, four landmark first-instance decisions – Plant-e v Bioo (The Hague Local Division, or LD), CFI 376/2023 (Brussels LD), CFI 471/2023 (Mannheim LD), and N.J. Diffusion v Gisela Mayer (Paris LD) – established, refined, and finally harmonised the analytical framework for assessing functional equivalence under Article 26 of the Agreement on a Unified Patent Court and Article 69 of the European Patent Convention together with its Protocol on Interpretation.
The European framework resonates closely with the approach already codified in Article 89(5) of the Turkish Industrial Property Code, which defines the doctrine of equivalence in explicitly technical-functional terms. Under this provision, the protection conferred by a patent extends not only to what is literally claimed but also to elements that are equivalent to those expressed in the claims, provided that they perform substantially the same function in substantially the same way and produce substantially the same result.
This three-part formula (‘function–way–result’) creates a narrowly technical standard that excludes policy considerations such as fairness or foreseeability. Turkish courts, particularly the Ankara and Istanbul specialised intellectual property courts, consistently apply this approach by examining whether the allegedly infringing feature carries out the same operation, by the same technical means, to reach the same outcome as the claimed invention. Only when all three conditions are met is infringement by equivalence recognised.
UPC jurisprudence: convergence and divergence
When the Turkish courts’ approach is compared to the UPC jurisprudence, the closest conceptual match is found in the Mannheim LD’s decision of June 6 2025 (CFI 471/2023). However, the Mannheim panel insisted that infringement by equivalence must be excluded whenever there is no technical-functional equivalence between the patent’s feature and the alleged variant. Just like the Turkish courts, the Mannheim LD has also focused purely on technical substitutability and did not consider whether the patentee deserves broader protection or whether third parties could have foreseen the variant.
By contrast, the earlier Plant-e v Bioo judgment of the Hague LD reflects a much broader and more policy-oriented conception of equivalence. The Hague LD applied a four-question framework combining technical and normative considerations:
Whether the variant achieves the same technical result;
Whether extension of protection would be fair to the patentee;
Whether legal certainty for third parties would be preserved; and
Whether the variant remains novel and inventive over prior art.
The approach of the Hague LD expands well beyond the Turkish courts’ approach as it introduces balancing factors of fairness and foreseeability.
Partial alignment across jurisdictions
The Brussels LD took a step closer to the Turkish courts’ approach without a full alignment.
In its January 2025 ruling (CFI 376/2023), the Brussels judges reduced the equivalence test to a functional-effect criterion, asking only whether the modified means perform the same function or at least achieve the same effect.
While this brings the analysis closer to the “function” and “result” prongs of Article 89(5) of the Turkish Industrial Property Code, it omits the intermediate requirement that the element operate in the same way.
Turkish courts, by contrast, treat this “way” component as indispensable. This ensures that mere similarity of purpose or outcome is insufficient unless the technical mode of operation is also equivalent.
Finally, the Paris LD’s decision in N.J. Diffusion v Gisela Mayer (August 1 2025, CFI 363/2024) represents the culmination of UPC convergence towards the same technical ideal, even if phrased more simply.
After reviewing Plant-e and the Brussels and Mannheim LD decisions, the Paris panel adopted what it called the “lowest common denominator” test: whether the modified or substitute means perform essentially the same function to achieve essentially the same effect.
This rule omits explicit reference to the “same way” criterion but, in practice, embodies the same spirit of functional-result equivalence that underlies the Turkish courts’ approach.
The court denied equivalence precisely because the accused product’s component served a different function and therefore produced a different effect. The reasoning is perfectly compatible with the outcome a Turkish court would likely reach.
Towards a shared European standard
In short, the Mannheim LD’s reasoning most faithfully mirrors the Turkish court’s approach. Both adopt a purely technical and objective analysis that asks whether the accused embodiment performs the same function, in the same manner, with the same result.
The Brussels and Paris approaches can be viewed as partial reflections of this rule, capturing its functional essence but simplifying its structure.
The Hague’s Plant-e framework, on the other hand, stands furthest apart, introducing equitable and policy dimensions foreign to the Turkish case law.
What is noteworthy is that while the UPC initially experimented with broader, policy-driven tests, its subsequent evolution – especially in Mannheim and Paris – has gravitated towards the strict technical equivalence model that the Turkish legislature had already enshrined.
Thus, Turkey’s (officially, Türkiye’s) codified approach and the UPC’s case law are now converging upon a shared European standard: one that defines equivalence not through notions of fairness or foreseeability but through objective functional identity within the bounds of the claims.
