The taking of evidence only comes into play when there are contested issues of fact that turn out to be decisive for the court’s ruling. As in any civil action, the court cannot just explore the facts if they are not relevant under the court’s legal analysis and applicable to the requested relief based on the parties’ factual contentions. Because of the above-explained, highly balanced and effective system of procedural obligations to substantiate contentions and denials, orders for evidence are clearly the exception in a German patent infringement action.
If the taking of evidence is necessary, the court must order to do so. This will typically only be done after an oral hearing, but it is procedurally also possible ahead of the first hearing, particularly if expert reports are involved (cf. Section 358a(4)). The order for evidence generally requires a formal written order identifying the contested facts and the evidence, particularly naming the witnesses and experts as well as the party that has taken recourse to the evidence (Section 359). The latter point is relevant because the taking of evidence is generally only admissible if one of the parties has taken recourse to the evidence at issue. Expert evidence is the most important exception: the court can call for an expert opinion even if the parties have not expressly requested it. Naming the party that has taken recourse does not yet imply anything on the burden of proof. The burden of proof only becomes relevant if the court, following the taking of evaluation of the evidence, cannot convince itself in a manner sufficient for ascertaining whether the contested issue of fact is true or not (Section 286). The party bearing the burden of proof bears the risk of this non liquet – that is, the risk that the court rules against the party bearing the burden of proof. In the German concept, these rules are considered substantive rather than procedural in nature.
The German Code of Civil Procedure provides for several means of evidence: experts, witnesses, records or documents, visual evidence taken on site and the examination of a party.
Only court-appointed experts are considered experts in terms of being a formal means of evidence. Experts retained by the parties to the litigation, and their corresponding reports, do not count as “evidence.” Rather, such reports just generally count as submissions by the respective parties. However, they do carry more weight (“qualified party submission”) depending on the qualifications and reasoning of the expert opinion, as the court cannot simply take on a different view without providing express reasons and sources as to why certain scientifically founded arguments are dismissed. Thus, filing party expert opinions can be a relevant element and can make the court more inclined to resort to an independent expert. Though rare in practice, a party expert may be allowed to speak during the hearing, but, again, this is procedurally only considered as a party representative – not an “expert witness” – speaking. Thus, there is no cross-examination or anything known from the Anglo-American trial-based system.
While the court has discretion as to expert selection (cf. Section 404(1)), the court usually asks the parties which experts are suitable for a specific technical field (cf. Section 404(4)). If the parties agree on an expert, the court generally must retain this expert (cf. Section 404(5)). The most difficult challenge is to identify experts in the pertinent technical field who are not (too) close to any of the parties (who are, in patent infringement cases, often leading companies in the field that also work closely with scientists), as the parties can reject experts for reasons of bias (cf. Section 406). This is also why the parties, when evaluating which experts are suitable, should be very careful when unilaterally contacting candidates. Once an expert has been identified and has indicated they are ready to render an opinion on the pertinent subject matter, the court formally appoints the expert and sets a term for the expert to submit a written report on certain issues set forth in the order for evidence (Section 411(1)).
The written report is submitted to the court, and the court provides it to the parties so that they have the opportunity to comment in writing on the report. Based on these statements, the court can specify further points, asking the expert to supplement the report. In many cases, the expert is summoned to a hearing to give the court and the parties a chance to ask questions about the report. The court may prepare such a hearing by way of a written order to give the expert a chance to prepare. During the hearing, the bench primarily leads the examination of the expert, but the parties (through their counsel) have the right to also ask questions. Even though the examination of experts is conducted in a manner similar to that of witnesses (the pertinent rules on witnesses apply mutatis mutandis to experts; cf. Section 402), experts are not referred to as “expert witnesses.” The latter term only refers to “knowledgeable persons” who are to be examined to obtain evidence regarding past facts and circumstances, or situations given in the past, that require special technical competence to be perceived (Section 414). These genuine “expert witnesses” are procedurally treated as witnesses, not as experts, for the purposes of the rules on taking evidence.
As stated above, only contested issues of fact can be subject to an expert opinion. This could, for example, pertain to a characteristic of the accused device that is not readily ascertainable (e.g., visible). While issues of law cannot be subject to expert evidence, and claim construction is generally considered an issue of law, certain aspects relevant to claim interpretation can be referred to an expert. A typical example is cases in which specific technical terms are used in the claims and not defined in the description but for which the skilled person at the priority date could have a defined understanding. If a claim, for example, uses the term “solution,” the parties could argue whether the term is limited to a strict molecular solution or if it could also cover certain suspensions. The experienced German infringement courts are rather reluctant, though, to resort to expert opinions in such cases unless there is no clear function indication in the patent-in-suit or any other documents that form the undisputed basis for the common general knowledge at the priority date based on which the skilled person is considered to have been operating.
It is important to note, though, that the bench cannot just rely on the expert when it comes to claim construction. The FCJ has set aside a number of decisions that did not reflect a genuine and independent reasoning of the infringement regarding claim construction but rather generally referred to an expert’s reasoning.149
While experts are typically retained to provide a written expert report on certain questions as set forth in the order for evidence, experts have also been retained by the court to attend a hearing and to assist the bench during the hearing by way of commenting on certain technical topics.150
While the taking of evidence by hearing witnesses is a key part of the provisions on evidence in the Code of Civil Procedure (Section 373–401, witnesses are rarely examined in German patent infringement proceedings. The main issue for which witnesses play a role is a prior-use right according to Section 12 of the Patent Act. This is different from a public prior use that would count as prior art and thus only be relevant for a stay of infringement proceedings. The prior-use right, under Section 12, is a genuine defense that does not challenge the validity of the patent but only establishes a right for the defendant to continue a certain use of the invention that had to be started before the filing or priority date. Other fields where witnesses can be relevant are with respect to the standing to sue or the infringing activities of the defendant.
The taking of evidence by hearing a witness requires offering this evidence by naming the witness and designating the facts regarding which the witness is to be examined (Section 373). The court cannot ex officio name a witness. The witness must be summoned to the hearing (Section 377), and the summons must include the designation of the parties, the subject matter of the examination and an instruction of the witness to appear at the set hearing date for the purpose of testifying before the court. The summons must also include the warning that failure to do so may be sanctioned by means of administrative coercion provided for in the law.
While affidavits do not count as witness evidence (only as a document), Section 377(3) provides that the court may instruct that the question regarding which evidence is to be taken be answered in writing should it believe that, in light of the content of the question regarding which evidence is to be taken and taking into consideration the person of the witness, it suffices to proceed in this matter. This written answer would qualify as witness testimony. Any other written declaration (or affidavit), or the record of witness testimony from another proceeding, would not qualify as witness evidence but only as evidence in the form of a “record or document.” While it is not excluded to tender and take evidence in this form, the court would need to take evidence by also hearing the witness if the opposing party requests this.151 Thus, while there is no general principle that the most direct evidence ought to be taken, the taking of evidence in the form of hearing a witness cannot be easily avoided by referring to written statements or affidavits.
Witnesses are only entitled to refuse to testify on the specific personal and factual grounds provided for in Sections 383 and 384. Among the personal grounds are certain personal relationships with any of the parties, as well as professional duties of confidentiality. Among the factual grounds is the right to refuse answers to questions that the witness would not be able to answer without disclosing a technical or trade secret.
The production of records or documents requires the party tendering the evidence to actually produce it (Section 420). If the document is in the possession of the opposing party, the evidence can only be offered by filing a petition that the court direct the opponent to produce the record or document (Section 421). Unless there is a specific substantive obligation under civil law to produce such a document (Section 422), the opposing party only has a procedural obligation to produce such a record or document when it previously also tendered evidence to that extent, even if this was only in the written stage of the proceedings (Section 423).
Thus, generally speaking, the parties are under no procedural obligation to voluntarily produce any documents in their possession. However, the court can order one of the parties or a third party to submit records or documents in their possession if any of the parties has made reference to it (Section 142(1)). The same applies for items that are in the defendant’s or a third party’s possession (Section 144(1)) if such items ought to be examined by the court or a court-appointed expert. While this modifies the general principle of the production of evidence by the party referring to it, it is not meant to enable full-scale document discovery. Rather, the record or document must be specifically referred to, and it must be substantiated why it is assumed to be in the possession of any of the parties or a third party. It is not possible to ask for the production of an entire document collection without specifying the relevance of its individual parts.
Furthermore, this mechanism is not meant to enable the conclusive pleading by the plaintiff, as a typical discovery mechanism would. Rather, the plaintiff must sufficiently substantiate the facts on which the asserted claims are based rather than just explore the facts that could enable such pleading by way of document production. With regard to patent infringement actions in particular, the case law of the FCJ has aligned the infringement court’s duties to issue such orders with the statutory requirements for an independent inspection claim provided for in Section 140c of the Patent Act (see 22.214.171.124 of this chapter). Thus, the defendant need only submit certain documents referred to by the plaintiff and pertaining to the showing of infringement if there is a certain likelihood of infringement and the production is necessary for showing infringement.152