Expert Evidence in German Civil Procedure

How expert evidence works in German civil courts

In German civil litigation, expert evidence is evidence the court commissions, not evidence the parties call. Under §§ 402–414 of the Code of Civil Procedure (Zivilprozessordnung, ZPO; see § 404a ZPO) the court selects the expert, frames the questions and directs the work; the expert then reports in writing and, where necessary, explains the report orally. Party-appointed experts still matter, but procedurally their reports count as qualified party submissions rather than formal proof. For businesses used to adversarial systems, this is the single most important difference to understand before a technical or valuation dispute reaches a German court.

The court-appointed expert (gerichtlicher Sachverständiger) acts as an assistant to the judge. Judges at the regional courts (Landgerichte) and Higher Regional Courts (Oberlandesgerichte) are generalists; in construction, IT, machinery, insurance or company valuation cases, the outcome often turns on what the expert finds. Experts are also used to establish foreign law and trade usages, although in those areas the court may also inform itself in other ways. A party that understands how to shape the evidence order, the choice of expert and the questions put to the expert will usually have more influence on the result than one that waits for the report.

Appointing the court expert and framing the questions

The court decides who is appointed and how many experts it needs (§ 404(1) ZPO). It may hear the parties on the person of the expert beforehand and may ask them to propose suitable candidates (§ 404(2), (4)). Where publicly appointed and sworn experts (öffentlich bestellte und vereidigte Sachverständige) exist for a field, the court should normally use them (§ 404(3)). If the parties agree on a particular person, the court must follow that agreement (§ 404(5)), which is a useful lever where both sides prefer a recognised specialist over an unknown name from a court list.

The court also leads the expert's work (§ 404a ZPO). It can instruct the expert on the type and scope of the task, should brief the expert before framing difficult questions, and — crucially — determines which facts the expert must assume where facts are disputed (§ 404a(3)). Instructions to the expert must be communicated to the parties (§ 404a(5)).

Influencing the evidence order

The evidence order (Beweisbeschluss) sets the questions. Parties can and should comment on draft questions, propose additional ones and object where a question already assumes a contested fact. Poorly framed questions are a common reason for a report that answers the wrong issue and for costly supplementary rounds.

• Ask the court to define disputed connecting facts (Anschlusstatsachen) before the expert starts.
• Propose questions that match the legal test, for example the standard of care, the defect or the causal chain.
• Raise access issues early: site inspections, plant shutdowns, source code or data rooms.
• Flag confidentiality needs before documents go to the expert.

Duties of the court expert and challenges for bias

Section 407a ZPO lists the expert's core duties. The expert must check immediately whether the assignment falls within their field and can be completed within the deadline without involving other experts, and must disclose any grounds that could justify doubts about impartiality (§ 407a(1), (2)). The expert may not delegate the assignment and must name any assistants who did more than minor auxiliary work (§ 407a(3)). Where costs are likely to be clearly disproportionate to the value in dispute or substantially exceed the advance requested, the expert must warn the court in good time (§ 407a(4)).

A party may challenge an expert on the same grounds as a judge (§ 406(1) ZPO). Timing is strict: the application must be filed before the expert is heard and, at the latest, within two weeks after the appointment order was announced or served (§ 406(2)). Later challenges are admissible only if the party shows it could not have raised the ground earlier without fault. Grounds that arise later — for instance from the content of the report or from one-sided contact with a party — must be raised promptly once known.

Testing the report: objections, questioning and new reports

Most expert evidence is given in writing. The court sets a deadline for the signed report and may impose administrative fines of up to EUR 3,000 per instance if the expert misses it after a warning (§ 411(1), (2) ZPO). Once the report is in, the parties must communicate their objections, requests concerning the report and supplementary questions within a reasonable period; the court may set a deadline, and late submissions can be excluded under the rules on late pleading (§ 411(4)).

The court can order the expert to explain the report orally, to supplement it in writing or to attend by video link (§ 411(3)). In practice, a party that files reasoned objections and asks for the expert to be summoned will usually obtain an oral hearing; this is the closest German procedure comes to cross-examination. Questioning is conducted primarily by the court, with counsel putting supplementary questions. If the court considers the report insufficient, it may order a new report by the same or a different expert (§ 412).

Party experts and private expert reports

A party-appointed expert's report (Privatgutachten) is not formal expert evidence under §§ 402 ff. ZPO unless both sides agree to treat it so. It is, however, a substantiated part of the party's pleading, and German courts are expected to engage with it. Where a party expert's reasoned report contradicts the court expert, the court generally has to address the contradiction — for example by putting the private report to the court expert or by ordering a further opinion — rather than simply following the court-appointed expert.

Party experts are therefore valuable in three phases:

1. Before the claim: to assess merits, quantify damages and decide whether to sue at all.
2. During the evidence phase: to draft questions, review the court expert's methodology and prepare objections.
3. At the hearing: to sit with counsel and suggest supplementary questions when the court expert explains the report.

Costs of a private report can be recoverable as necessary litigation costs in some circumstances, but recovery is not automatic; budgets should assume that much of the cost remains with the party. For the broader cost picture, see our insight on litigation costs and cost shifting.

Independent evidence proceedings before or during a dispute

Independent evidence proceedings (selbständiges Beweisverfahren, §§ 485–494a ZPO) allow a party to secure expert evidence outside or ahead of the main action. If no action is pending, a party with a legal interest may apply for a written expert report on the condition or value of a thing, the cause of damage or a defect, or the cost of remedying it (§ 485(2)); a legal interest is assumed where the finding may help avoid litigation. During or outside proceedings, evidence may also be taken where the opponent consents or where evidence risks being lost (§ 485(1)).

The procedure is widely used in construction, plant engineering and lease disputes. Its advantages for businesses are practical:

• The results have the same effect in a later action as evidence taken by the trial court (§ 493(1) ZPO).
• Service of the application suspends limitation for the claims concerned (§ 204(1) no. 7 of the Civil Code, Bürgerliches Gesetzbuch, BGB).
• The court can invite the parties to a discussion where a settlement seems likely and record a settlement (§ 492(3)).

There is a counterweight: once evidence has been taken and no action is pending, the opponent can ask the court to order the applicant to sue within a deadline; if the applicant does not, it must bear the opponent's costs (§ 494a ZPO). Contractual expert determination clauses (Schiedsgutachten) are an alternative; the start of an agreed expert procedure also suspends limitation (§ 204(1) no. 8 BGB). See our note on limitation periods.

Liability, costs and confidentiality of expert evidence

A court-appointed expert who intentionally or with gross negligence delivers an incorrect report is liable for the loss a party suffers through a court decision based on it (§ 839a BGB), subject to the duty to use available remedies first. Experts' fees follow the Judicial Remuneration and Compensation Act (Justizvergütungs- und -entschädigungsgesetz, JVEG), and the court will usually require the party bearing the burden of proof to pay an advance before the expert is instructed.

Confidential business information often has to reach the expert — source code, formulas, cost calculations. Confidentiality measures modelled on §§ 16–20 of the Trade Secrets Act (Gesetz zum Schutz von Geschäftsgeheimnissen, GeschGehG) are now available in civil proceedings generally (§ 273a ZPO). Our insight on confidential information in litigation explains how to request them before the expert receives the material.

Expert evidence in arbitration and the Commercial Courts

In arbitration seated in Germany, the tribunal may appoint experts, but party-appointed experts are far more common and are examined at the hearing (§ 1049 ZPO). The new Commercial Courts under the Judiciary Strengthening Act operate under the ZPO, so court-appointed expert evidence remains the rule there, although organisational hearings give parties more room to agree on the process. See international arbitration and Commercial Courts.

How TRW & Co helps with expert evidence

We advise companies on technical, construction, IT, valuation and damages disputes from the first assessment of evidence to the final hearing. In practice that means selecting and briefing party experts, drafting proposals for the evidence order and the questions to the court expert, monitoring the expert's independence and the two-week challenge period, and preparing reasoned objections and questioning when the report arrives. Where evidence is at risk or a claim needs to be quantified before suing, we assess whether independent evidence proceedings or a contractual expert determination is the better route. Our commercial litigation team works alongside the relevant industry specialists. To discuss a pending or threatened dispute, please contact us.