Best practice for handling foreign law

Background

In a dispute, a German court also has to decide questions of foreign law to the extent foreign law applies. This duty flows from Section 293 ZPO: the court is not limited to the evidence the parties bring, but is also authorised to draw on other sources and to order what is necessary to that end.

The court must determine foreign law of its own motion. How it obtains the relevant knowledge is in its sound discretion. Free-form evidence (Freibeweis) applies: the court may use any means of evidence and any source of knowledge. The court's options include commissioning an expert opinion on foreign law. The expert's role, however, is limited to answering the court's evidentiary questions about foreign law. The determination, interpretation, and application of the private international law (PIL) in force in Germany, and the decision of the specific case (fact-finding and application of foreign law to those facts) remain the court's own task.

Where the decision turns on foreign law, the court must discuss this with the parties (right to be heard) and give them an opportunity to address its determination and content. Where the court has formed a preliminary view of the content of foreign law, for example based on its own research, it shares that view with the parties (Hamburg Guidelines (2023), Art. 2 § 2 No. 2).

The parties to the dispute may help the court determine foreign law, but they are generally not obliged to do so beyond their general duty to promote the proceedings and to cooperate. Foreign legal rules are treated as rules of law, not as facts, so the principles of burden of pleading and proof do not apply (Hamburg Guidelines (2023), Art. 1 § 1 No. 3 referring to BGH, order of 24 August 2022 – XII ZB 268/19). For tactical reasons each party should nonetheless make submissions on foreign law. That alone makes it worth being represented in an international dispute by experienced, specialized counsel who can run the case confidently and persuade the court.

Under the BGH's settled case law, the competent court must determine and apply foreign law in the way it is, or would be, applied by the courts of the respective country (see BGH, judgment of 5 July 2023 – IV ZR 375/21 marginal no. 27).

The application of foreign law itself is, according to the BGH, not reviewable on revision (referring to Section 560 ZPO in conjunction with Section 545 ZPO). The revision court is in principle bound by the findings of the court of appeal on the content of foreign law. In other words: German law is reviewable on revision; foreign law is not. The determination of foreign law, however, is subject to review by the highest court (see BGH, judgment of 5 July 2023 – IV ZR 375/21 marginal no. 24).

The Hamburg Guidelines

The "Hamburg Guidelines on the Determination and Application of Foreign Law in German Proceedings" (Hamburg Guidelines), developed through close exchange between practice and academia and published by the Max Planck Institute for Comparative and International Private Law in Hamburg, support courts, experts, and parties (including their representatives) in handling foreign law in international disputes. They set out the relevant legal framework in compact form and offer a range of practical recommendations (Michaels/Schmidt, Die Hamburger Leitlinien zur Ermittlung und Anwendung ausländischen Rechts in deutschen Verfahren, NJW 2024, 24, with further background, content overview, and outlook).

The Hamburg Guidelines are primarily aimed at proceedings before civil courts, but apply in principle to other cases as well where German courts or authorities (for example, tax courts, criminal courts, asylum authorities, tax offices, civil registry offices) have to apply foreign law (Hamburg Guidelines (2023), preliminary remarks).

The Hamburg Guidelines do not address the international jurisdiction of German courts, because courts can and must answer that question independently on the basis of the relevant legal sources (for example, Brussels Ia Regulation, Brussels IIb Regulation, Sections 97 et seq. FamFG) (Hamburg Guidelines (2023), preliminary remarks).

Summary

The Hamburg Guidelines are a useful tool for practice.

The Hamburg Guidelines are licensed under the Creative Commons Licence CC-BY 4.0. Published by the Max Planck Institute for Comparative and International Private Law, Hamburg. Authors: Prof. Dr Ralf Michaels and Priv.-Doz. Dr Jan Peter Schmidt. The Hamburg Guidelines are available here.

Reference: Poleacov, P. (2025). Best practice for handling foreign law. INN.LAW. https://inn.law/en/perspectives/hamburg-guidelines/

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