Details on the operations of reduction to the legal maximum and consolidation of sentences

Jan 27, 2025

Introduction

In the context of a criminal investigation, judicial authorities today have access to particularly sophisticated investigative techniques. Among them are vehicle geolocation and audio surveillance (bugging), which make it possible to track a person’s movements or record conversations without their knowledge. These techniques are effective, but they interfere with the right to privacy. For this reason, they are strictly regulated by law.

In a ruling dated November 18, 2025, the Criminal Chamber of the Court of Cassation examined several applications for nullity concerning the use of these investigative techniques. The case raised important questions: under what conditions may investigators enter a private place to install a geolocation device? Is special authorization required? What happens when audio surveillance measures begin in France and continue abroad? Finally, who may request the annulment of an investigative act when rules relating to State sovereignty have not been respected?

Through this decision, the Court of Cassation clarifies the rules applicable to nullities during the investigative phase and recalls the safeguards governing the use of the most intrusive investigative techniques.

I. The Strict Regulation of Geolocation and Intrusion into a Private Place

a) The Authorization Required for Vehicle Geolocation

In the context of a judicial investigation, vehicle geolocation cannot be decided freely by investigators. It must be authorized by the investigating judge, in accordance with Article 230-33 of the Code of Criminal Procedure.

This authorization must be:

  • in writing;

  • reasoned (that is, justified by the needs of the investigation).

However, the law specifies that this decision is not subject to appeal. This means that the person concerned cannot immediately challenge the authorization itself. Nevertheless, they may later request the annulment of the measure if they believe that the legal conditions were not respected.

The issue does not end with authorization to geolocate. The technical device must also be installed on the vehicle. Yet this installation may require intrusion into a private place, which raises an additional legal difficulty.

Article 230-34 of the Code of Criminal Procedure provides that specific authorization is required when the installation (or removal) of the device involves:

  • entering a private place used for storing vehicles, goods, or equipment;

  • or intervening on a vehicle located in such a place;

  • without the knowledge or consent of the owner or occupant.

In other words, the infringement of privacy is twofold: there is both surveillance of the vehicle and intrusion into a protected space. This double interference justifies dual judicial control.

The Court of Cassation had recently reiterated the importance of this special authorization. In the present case, it clarifies its practical scope.

b) The Possibility of Visually Entering the Private Place

In this case, the investigating judge had issued two separate decisions:

  • one authorizing the capture of images in the common areas of an underground parking garage;

  • the other authorizing the geolocation of a vehicle parked in a closed private garage within that same parking facility, as well as authorizing investigators to enter the garage to install the device.

To precisely locate the vehicle, investigators used an endoscope—that is, a device allowing a camera to be inserted into a closed space to observe its interior. This enabled them to identify the garage containing the vehicle and capture images from inside the private space.

The defendants argued that this operation constituted an additional infringement of privacy and was not covered by the authorization granted. According to them, no specific decision permitted visual capture inside the private garage.

The Court of Cassation rejected this argument. It held that the authorization given by the investigating judge to enter the private place for the purpose of installing the device necessarily implies the possibility of entering it visually. Indeed, it would be illogical to authorize a physical intrusion without allowing investigators to see what they are doing.

In other words, the capture of images carried out solely for the purpose of installing the geolocation device does not require separate authorization, provided it is strictly linked to that installation and falls within the scope of the existing authorization.

The Court thus adopts a pragmatic approach: it verifies that investigators remained within the limits of their authorized mission. As long as the images were not used for purposes other than installing the device, there is no ground for nullity.

II. Cross-Border Audio Surveillance and the Issue of Public Policy Nullities

a) The Continuation of Audio Surveillance Abroad

The case also raised a delicate issue: a vehicle audio surveillance measure that was installed in France and then continued while the vehicle traveled through several foreign States.

Audio surveillance is governed by Article 706-96 of the Code of Criminal Procedure. It allows the recording, without the knowledge of the persons concerned, of words spoken in a place or inside a vehicle. This constitutes a significant interference with privacy, which justifies strict regulation.

When the measure takes place in France, authorization by the investigating judge is sufficient. However, the situation becomes more complex when the vehicle leaves national territory.

This raises the issue of State sovereignty: may one State, without authorization, continue a surveillance measure on the territory of another State? In principle, any investigative operation carried out on the territory of a foreign State must comply with the rules of international judicial cooperation in criminal matters.

In this case, the applicants argued that the continuation of audio surveillance abroad violated the sovereignty of the States concerned and should result in the nullity of the acts.

The Court of Cassation, however, recalled that international judicial cooperation applies when an investigative act is carried out on foreign territory. In this instance, the device had been installed in France. The data capture resulted from the functioning of a device lawfully placed on French territory.

The Court thus adopted a technical analysis: as long as the material act of installation occurred in France and no additional intervention was carried out abroad, the measure does not necessarily constitute direct interference on foreign territory.

This interpretation limits the situations in which a request for international judicial cooperation is mandatory.

b) Public Policy Nullity and Standing to Act

Finally, the ruling provides important clarifications regarding the regime of public policy nullities.

In criminal procedure, not all irregularities automatically lead to the annulment of an act. In principle, it is necessary to demonstrate:

  • either the violation of a substantial procedural requirement;

  • or the existence of prejudice, meaning harm caused by the irregularity.

However, certain rules are matters of public policy. Their violation may result in nullity even without proof of personal prejudice.

The question raised was therefore the following: does a violation of the principle of sovereignty of a foreign State constitute a public policy nullity that may be invoked by a person under investigation?

The Court recalls a fundamental principle: to seek nullity, one must have standing to act. This means that only the person whose rights have been directly affected may request annulment.

The principle of sovereignty primarily protects the interests of the State concerned, not those of the person being prosecuted. Consequently, a suspect cannot systematically invoke a breach of a foreign State’s sovereignty to obtain the nullity of an investigative act.

In other words, the alleged violation must concern a personal right of the applicant. Otherwise, the request is inadmissible.

This solution is consistent with the established case law of the Court of Cassation, which seeks to prevent excessive use of nullity proceedings as a procedural strategy.

Conclusion

Through its ruling of November 18, 2025, the Criminal Chamber of the Court of Cassation provides important clarification on the regime of nullities concerning intrusive investigative techniques.

On the one hand, it confirms that the authorization granted by the investigating judge to enter a private place in order to install a geolocation device necessarily implies the possibility of visually entering that space, provided that such visual capture is strictly linked to the execution of the authorized mission.

On the other hand, it clarifies the rules applicable to cross-border audio surveillance, adopting a concrete approach based on the place where the device was installed. It also recalls that a violation of the principle of State sovereignty may only be invoked by the party whose rights are directly affected.

This ruling thus illustrates the constant search for balance between the effectiveness of criminal investigations and the protection of fundamental freedoms. It shows that while modern investigative techniques are permitted, their use remains strictly regulated and subject to judicial oversight, with the judge serving as the guardian of rights and freedoms.