Obtaining Evidence Located in Switzerland – ProtonMail User Data as an Example

Two Methods, Depending on Who Controls the Evidence

When parties to civil litigation in foreign countries need to obtain evidence situated in Switzerland, they have, in principle, two options: they can either rely on the power and proceedings of the court hearing the case or seek, via that court, the assistance of a Swiss court to obtain the evidence. The first option is mainly relevant if the evidence is controlled by a party (i.e., the claimant or defendant) in the main proceedings. In cases where a third party in Switzerland controls the evidence, the court must use international legal assistance mechanisms; otherwise, it may violate Swiss sovereignty, and those involved risk criminal prosecution. Each year, a handful of reports are filed with the Swiss Federal Office of Justice regarding prohibited acts committed on behalf of a foreign state under Article 271 of the Swiss Criminal Code.

The Hague Evidence Convention

The most frequently used mechanism for obtaining evidence in Switzerland is provided by the Hague Convention of 18 March 1970 on the Taking of Evidence Abroad in Civil or Commercial Matters (Hague Evidence Convention). The Convention currently has 69 contracting parties (as of April 2026), including the United States, the United Kingdom, France, Germany, India, Brazil, Singapore, South Korea, and other European and Asian countries. However, some prominent countries such as Canada and Japan are not parties to the Convention, making evidence requests from these jurisdictions more complex. Additionally, Switzerland has entered into bilateral agreements with several countries that authorize direct contact between judicial authorities or complement the Hague Conventions.

Letters of Request Procedure

The Hague Evidence Convention establishes two primary methods for obtaining evidence abroad in civil or commercial matters: Letters of Request (Chapter I) and taking of evidence by diplomatic officers, consular agents, or commissioners (Chapter II). Under the Letters of Request procedure, a judicial authority in the requesting state issues a detailed Letter of Request to the competent Swiss cantonal authority or to the Swiss Federal Department of Justice and Police in Bern, which will forward the request to the appropriate cantonal authority. This Letter of Request must include specific information such as the authorities involved, parties' details, nature of the proceedings, evidence sought, and any special procedures required. The competent Swiss authority will then proceed to the taking of evidence as per Swiss civil procedure and return the gathered evidence to the requesting authority through the same channels. The second method, which involves diplomatic officers, consular agents, or commissioners taking evidence in Switzerland with permission from the Swiss Federal Department of Justice and Police, is not discussed here (see the update below — this method has become considerably more attractive since 1 January 2026).

Adapting Legal Procedures to Swiss Requirements

Judicial assistance for obtaining evidence typically involves a straightforward process where a foreign court submits a request to the competent Swiss court, which then handles evidence collection. However, in certain cases, additional adjustments are necessary to reconcile differences between legal systems, such as aligning U.S. discovery procedures with Swiss procedural law and its reservations to the Hague Evidence Convention.

Importantly, Letters of Request and supporting documents must be submitted in the language of the executing cantonal authority—German, French, or Italian—or accompanied by a translation. The execution of a letter of request follows the Swiss Civil Procedure Code. If the requesting state asks for its laws to be applied, this will be accommodated unless it conflicts with Swiss law or is impractical. For instance, affidavits can be accepted with the witness's consent. Cross-examination, though not part of Swiss procedure, may also be allowed under the supervision of a Swiss judge, who ensures that the witness's rights are protected and that no coercion is used.

No Fishing Expeditions

Switzerland does not entirely exclude assistance in pre-trial discovery, but it imposes strict requirements. Requests must be sent by a competent foreign court, not directly by the parties, and must precisely describe the evidence needed and its purpose. General or vague requests aimed at discovering unspecified evidence ("fishing expeditions") are rejected. The request must establish a direct and necessary link to the pending proceedings. Additionally, requests must not harm the interests of the person concerned, such as business or banking secrecy.

Case Study: Obtaining ProtonMail User Data

In recent years, we have assisted several U.S.-based parties in obtaining user data from ProtonMail, a service provided by Proton AG in Geneva, Switzerland. Known for its strong encryption and privacy protections, ProtonMail has occasionally been misused for defamation, harassment, blackmail, and breach of confidentiality, leading to legal actions.

Unveiling an anonymous perpetrator (AI).

Certain U.S. states use the "John Doe" or "Jane Doe" lawsuit, enabling plaintiffs to initiate proceedings against unidentified defendants and use discovery to uncover the identities of anonymous individuals. This can involve issuing subpoenas to websites or Internet Service Providers for data like email addresses and IP addresses. However, such subpoenas cannot be directly served on ProtonMail in Switzerland. Instead, the process must adhere to the requirements of the Hague Evidence Convention, including Switzerland’s reservations to the convention and its procedural core principles.

The adaptation of a U.S. subpoena into a Hague Request letter—a task typically performed by U.S. attorneys—can be complex and is an area where we can offer valuable assistance. When properly handled, it was possible to obtain from ProtonMail all available data (noting that the emails themselves are encrypted and not accessible), which in at least one case led to the identification of a perpetrator and a substantial settlement in a defamation case.

If you want to leave no stone unturned, let’s discuss how legal assistance to obtain evidence in Switzerland could help your case.

Update (July 2026): Remote testimony from Switzerland no longer requires prior authorization

Since this article was published, Switzerland has significantly liberalized the second method under the Hague Evidence Convention. As of 1 January 2026, under the revised Art. 11 of the Swiss Private International Law Act (PILA) and Switzerland's revised Declaration No. 5 to Articles 15–17 of the Convention, persons located in Switzerland may be examined or heard by or for a foreign court in civil proceedings by video or telephone conference without prior authorization by the Swiss authorities. Instead, a notification must reach the Federal Office of Justice, with a copy to the central authority of the canton concerned, in principle at least 14 days before the hearing. Participation remains strictly voluntary, and the notification must meet a detailed list of requirements.

The new regime applies not only between contracting states of the Convention but erga omnes — that is, also in relation to non-party states such as Canada or Japan (Art. 11(3) PILA). The revised law further codifies that a party located in Switzerland may voluntarily transmit its own submissions and evidence to a foreign court (Art. 11(2) PILA).

A word of caution: failure to comply with the conditions of the revised Declaration No. 5 may still expose the persons involved to criminal liability under Art. 271 of the Swiss Criminal Code, and an informal assessment by the Federal Office of Justice does not bind the criminal courts. Involving Swiss counsel before the examination remains the prudent course.