Illicit Evidence in Court: A Landmark Decision of the Court of Cassation

Imagine: you are the owner of a flat in Strasbourg, and you overhear a conversation in which your tenant threatens to damage the property. You record this conversation with your phone, then forward it to the police. But then the tenant's lawyer cries foul: the recording is an illicit piece of evidence, obtained without consent. The question then is: can a judge use this evidence?

Thousands of landlords and tenants ask themselves this question every year. Because under French law, the principle is that evidence must be obtained fairly. Yet the Court of Cassation, in a judgment of 1 December 2020, has just shaken up this rule. It held that where the origin of evidence remains uncertain despite investigations, its inclusion in the case file is not irregular solely on the ground that the absence of involvement of a public official has not been proved. In practical terms, this means that sound recordings made by private individuals can be validated, even if it is not known exactly how they were obtained. A small revolution for the law of evidence.

This decision, handed down in a criminal case, has major repercussions for property and land law. Whether you are a landlord in Saverne, a tenant in Strasbourg, or a developer in the Grand Est region, this case law can change the game in a dispute. Full analysis.

The Facts: A Story Like Many Others

The case began with an investigation into a breach of judicial supervision. Two individuals, suspected of having breached their obligations, were taken into custody. During the search, investigators found sound recordings attached to an anonymous letter. These recordings, which appeared to prove the offences, were placed in the case file. But no one knew exactly who had made them, or under what conditions. The lawyers for the accused cried scandal: this evidence was illicit, obtained in breach of source confidentiality or by an unauthorised third party. They sought its outright annulment.

The Strasbourg Criminal Court, and then the Indictment Division of the Colmar Court of Appeal, rejected this request. The judges held that, despite investigations, it was impossible to determine whether a public official had participated in the recording. Accordingly, they could not declare the evidence irregular. The accused appealed to the Court of Cassation. But the Court of Cassation upheld the judgment: the inclusion of these recordings was valid, even without knowing their exact origin. A development that sets a precedent.

You may have experienced this situation: a neighbour in Saverne recording an altercation, a tenant filming a maintenance defect, a landlord capturing defamatory remarks. The line between lawful and unlawful evidence is sometimes blurred. And this decision clarifies a key point: uncertainty as to the origin of the evidence is not sufficient to have it struck out.

The Court's Reasoning — Explained

To understand the decision, we must go back to the principles. Article 427 of the Code of Criminal Procedure provides that evidence may be produced by any means, unless otherwise provided. But Article 6 of the European Convention on Human Rights requires a fair trial, which includes the fairness of the evidence. In civil matters, Article 9 of the Code of Civil Procedure provides that each party must prove the facts necessary for the success of its claim. Finally, Article 226-1 of the Criminal Code prohibits recording words spoken in private without the consent of the speaker. Any evidence obtained unfairly may be excluded.

In this case, the defence argued that the recordings were void because their origin was unknown, which meant it could not be guaranteed that they had not been obtained by a state agent in breach of the rules. But the Court of Cassation held that uncertainty does not favour nullity. It ruled that where the conditions under which an item of evidence was collected remain uncertain despite investigations, its inclusion in the case file cannot be declared irregular solely on the ground that the absence of direct or indirect involvement of a public official has not been established. In other words, it is for the person challenging the evidence to prove that it was obtained unlawfully, not for the court to prove that it is lawful.

This reasoning marks a shift: it protects journalistic source confidentiality (since the recordings could have come from a journalist) and prevents potentially crucial evidence from being excluded on a mere doubt. For landlords and lessors, this means that evidence collected by a third party (neighbour, caretaker, private detective) may be admissible, even if it is not known exactly how it was obtained.

What This Means for You — Practically

In practical terms, if you are a landlord in Strasbourg and you receive an anonymous recording proving that your tenant is subletting without authorisation, you can now use it in court. Previously, a judge might have excluded it due to uncertainty about its origin. Now, as long as you do not have proof of unlawful involvement by a public official, the evidence is admissible. Similarly, if you are a tenant in Saverne and you film a serious maintenance defect: if the video is placed on the case file without anyone knowing who filmed it, it will not be automatically struck out.

Let us take a concrete example: a Strasbourg landlord seeks to prove that his tenant caused water damage through negligence. He has an audio recording of the tenant's admission, made by a neighbour. The cost of repairs amounts to €5,000. Before this decision, the judge might have refused to use the recording, for lack of knowing whether the neighbour complied with the law. Now, the recording is admissible, and the landlord can obtain compensation. Conversely, if you are a tenant and your landlord uses dubious evidence, you will have to prove that it was obtained illegally to have it excluded.

If you are in this situation, you must act quickly: gather all the elements, even those of uncertain origin, but consult a lawyer before submitting them. Time limits for challenging evidence are short (often 15 days after its disclosure). Do not wait.

Four Tips to Avoid This Type of Dispute

• Never make a recording yourself without the other party's knowledge: this remains unlawful (Article 226-1 of the Criminal Code). Use a bailiff or a licensed private detective.
• Keep the original of any evidence: a recording, a video, an SMS. A copy may be challenged. Store it on a reliable medium (USB key, secure cloud).
• State the origin of the evidence: if you pass a document to a third party (journalist, investigator), state in writing how you obtained it. This will avoid uncertainty.
• Consult a lawyer before submitting evidence to the case file: a lawyer specialising in property law can assess its admissibility and save you from a late rejection. A simple 30-minute consultation can save you months of proceedings.

Further Reading: Related Case Law and Developments

This decision is part of a line of case law favourable to the admission of evidence, even if imperfect. For example, the Court of Cassation, in a judgment of 10 January 2019 (no. 18-80.123), had already validated the use of recordings made by a private individual, provided they were necessary for the exercise of his defence. Conversely, the European Court of Human Rights, in the case of Schenk v. Switzerland (1988), held that the use of unlawful evidence does not necessarily violate the right to a fair trial if the proceedings as a whole are fair.

The trend is therefore towards greater flexibility, but with safeguards: the evidence must be useful and must not infringe the rights of the defence. In the future, we can expect judges to require greater transparency as to the conditions of collection, but to be less ready to exclude evidence solely on the ground of its doubtful origin. A development to watch closely for property professionals.

Key Points to Remember

1. Uncertainty as to the origin of evidence does not automatically make it inadmissible. It is for the person challenging it to prove its unlawfulness.

2. Journalistic source confidentiality is protected: the courts cannot require a journalist to reveal the origin of a recording in order to validate it.

3. In property matters, this case law applies: whether for a tenancy dispute, an easement or a neighbourhood nuisance, evidence collected by a third party may be used.

4. Beware of crossing the line: if you are the one who made the recording, you must comply with the law. Consult a lawyer before acting.

5. React quickly: challenges to evidence must be raised in limine litis (before any defence on the merits). After that time, the evidence is definitively admitted.

Are you in a similar situation? A first 30-minute consultation with Maître Zakine (€45) can save you months of proceedings — and often much more. Book an appointment →