This page deals with evidence in the course of an action. Measures taken before or alongside the action to obtain or preserve evidence (saisie, inspection, freezing of assets) are covered on a separate page: “Saisie and preservation of evidence”.
General framework
Burden of proof
The burden of proof of facts lies with the party relying on those facts (A54 UPCA). This principle is broadly shared by all the Member States (Actori incumbit probatio).
A party relying on a fact that is contested (or likely to be contested) must indicate the means of evidence to prove it and produce the evidence available to it; failing that, the Court takes this into account (R171.1 and R172.1 RoP UPC). A fact that is not specifically contested is held to be true as between the parties (R171.2 RoP UPC).
Reversal of the burden of proof
If the subject-matter of a patent is a process for obtaining a new product, any identical product made without the proprietor’s consent is, in the absence of proof to the contrary, deemed to have been obtained by the patented process (A55(1) UPCA).
The same presumption applies where (A55(2) UPCA):
- there is a substantial likelihood that the identical product was made by the patented process;
- and the proprietor has been unable, despite reasonable efforts, to determine the process actually used.
In adducing proof to the contrary, the legitimate interests of the defendant in protecting its manufacturing and trade secrets are taken into account (A55(3) UPCA).
Free evaluation
The Court evaluates evidence freely (A76(3) UPCA), and the representative must not misrepresent the facts (see “Representation before the UPC”).
Means of evidence
The means of evidence include in particular (R170.1 RoP UPC):
- written evidence (documents, written witness statements, plans, drawings, photographs);
- expert reports and reports on experiments carried out for the purpose of the proceedings;
- physical objects (devices, products, embodiments);
- electronic files and audio or video recordings.
Possible means of obtaining evidence include hearing the parties, requests for information, production of documents, hearing witnesses, expert opinions, inspection, comparative tests and experiments, and sworn written statements (affidavits) (A53(1) UPCA and R170.2 RoP UPC).
Witnesses
Written statement
A party wishing to rely on witness evidence lodges a signed written statement of the witness (or a summary of the testimony), in which the witness acknowledges the duty to tell the truth and the liability for failing to do so, and which states the witness’s relationship with the party and any conflict of interest (R175 RoP UPC).
Hearing
The Court may order a witness to be heard of its own motion, where the written statement is challenged, or at the request of a party setting out the reasons for the hearing, the facts to be confirmed and the language of the testimony (R176 and R177.1 RoP UPC).
The order summoning the witness specifies in particular the facts on which the witness will be examined (by the Court and the parties), the reimbursement of expenses, the language and any interpretation, and the witness’s rights and obligations (R177.2 and R177.3 RoP UPC). The examination is limited to what is necessary (A53(2) UPCA).
Experts
Party experts
The parties may produce such expert reports as they consider useful; if summoned, the expert must assist the Court impartially, that duty overriding any duty to the party that retained him or her (R181 RoP UPC).
But the expert does not replace the judge: claim interpretation is a question of law, and the Court may not leave it to an expert; likewise, it is for the judge, not the expert, to assess the knowledge of the skilled person (UPC, Court of Appeal, 30 Apr. 2025, Insulet v. EOFlow, UPC_CoA_768/2024, headnotes 1 and 2).
Court expert
Where it has to resolve a technical or other question, the Court may, of its own motion and after hearing the parties, appoint a court expert, who must offer the required guarantees of expertise, independence and impartiality (R185 RoP UPC). The presence of technically qualified judges on the panels does, however, make this less necessary than elsewhere (A8(5) and (6) UPCA).
Experiments ordered by the Court
On a reasoned request of a party, the Court may order an experiment to prove a fact; the order appoints the expert and sets the conditions and the time limit for the report; the parties may comment, and the expert may be heard (R201 RoP UPC).
Production of evidence
At the request of a party that has presented reasonably available and plausible evidence and that specifies evidence in the control of the opposing party or a third party, the Court may order its production, subject to the protection of confidential information; no one may be compelled to incriminate himself or herself (A59(1) UPCA). The same order may cover banking, financial or commercial documents of the opposing party (A59(2) UPCA).
The request is made during the written or interim procedure; the order specifies the conditions, the form, the time limit for production and the penalty incurred, and the Court takes a refusal to comply into account (R190 RoP UPC). The order may be appealed (R220.1(c) RoP UPC).
Communication of information
The Court may also, on a reasoned request, order the opposing party or a third party to communicate the information referred to in Article 67 (origin and distribution channels, quantities and prices, identity of third parties involved) or any other information reasonably necessary to advance the party’s case (A67 UPCA and R191 RoP UPC). Such communication may even be ordered at the provisional measures stage, where there is urgency and the order is proportionate (UPC, Court of Appeal, 14 Feb. 2025, Abbott v. Sibio, UPC_CoA_382/2024, headnote).
Be careful with what is communicated in this way: information handed over to the opposing party without a confidentiality order based on Rule 262A loses its confidential character (UPC, Court of Appeal, 18 March 2026, EOFlow v. Insulet, UPC_CoA_930/2025, headnote; see “Procedural principles”).