Constitution de partie civile par le maire : un recours communal sans limite ?

Imagine: in Tarnos, a commune in the Landes, a property developer begins construction work without a building permit. The mayor, alerted by residents, decides to join as a civil party (i.e., claim damages for the harm suffered by the municipality) on behalf of the town. The municipal council passes a resolution authorising this. But what happens if the first-instance judgment does not satisfy the municipality? Can the mayor lodge an appeal (challenge the judgment before a higher court) without a new authorisation from the council?

This is precisely the question the Constitutional Council decided on 22 January 1990, in a decision that is now a reference. It directly concerns any owner, tenant or professional facing a dispute with a municipality: town planning, nuisance, expropriation, damage caused by public works. For if the municipality joins as a civil party against you, know that its mayor can pursue the procedure to the end without referring each stage to the municipal council.

This decision, made in the context of a priority preliminary ruling on the constitutionality (QPC) of Article L. 2122-22 of the General Code of Local Authorities, clarifies a crucial point: the authorisation to join as a civil party includes the right to exercise all means of recourse. In other words, once the municipal council has said 'yes', the mayor may appeal, lodge an appeal in cassation, and even withdraw the action, without a new vote. This provides legal security for municipalities, but also important information for their opponents.

The facts: a story like many that happen every day

The case originated in Chelles, in Seine-et-Marne. The municipality had been the victim of an offence (destruction of municipal property, it appears). The municipal council, by a resolution of 23 February 1987, authorised the mayor to 'take legal proceedings' (i.e., bring or defend a lawsuit) and more specifically to join as a civil party. The mayor therefore joined as a civil party before the criminal court. The court convicted the defendant, but the municipality considered the damages insufficient. The mayor lodged an appeal. However, the opposing party raised an incidental issue: they contested the admissibility of the appeal, arguing that the mayor had not received express authorisation from the municipal council to appeal.

The case went up to the Court of Cassation, which referred a preliminary question (a question of constitutionality) to the Constitutional Council. The Council had to determine whether Article L. 2122-22 of the General Code of Local Authorities, which allows the municipal council to delegate certain powers to the mayor, is consistent with the Constitution. In clear terms, can the mayor, without a new vote, exercise all means of recourse? Or must he come back before the municipal council each time?

The Constitutional Council said: yes, the authorisation given to the mayor to join as a civil party implies the power to exercise the means of recourse available in that action. It therefore upheld the legal provision. However, note: the decision specifies that this applies to means of recourse 'arising from a joinder as a civil party made during a judicial investigation'. What few people know is that if the mayor wishes to join as a civil party in a new proceeding (e.g., after another offence), a new authorisation from the municipal council will be necessary.

The reasoning of the court — dissected

The Constitutional Council examined Article L. 2122-22 of the General Code of Local Authorities, in the version then in force. This article allows the municipal council to delegate to the mayor, for the duration of his term, certain powers, notably that 'of bringing legal actions on behalf of the municipality' and 'of defending the municipality in actions brought against it'. The question was: does an authorisation 'to bring' an action include that of exercising the remedies against the decision rendered in that action?

The Council answered in the affirmative, based on the principle of continuity of public action and municipal administration. It considered that the authorisation given to the mayor to join as a civil party is a global authorisation, covering the entire procedure, from first instance to the exhaustion of ordinary means of recourse (appeal) and extraordinary (appeal in cassation). In other words, the mayor is the legal representative of the municipality in that dispute, and he can take all necessary procedural decisions.

This reasoning fits into a logic of good administration: it would be absurd and paralysing to oblige the municipal council to meet at each stage to vote on a new appeal. It confirms previous practice, but also acts as a safeguard: the Council specifies that the delegation can only be for specific actions, and that the council can always end the delegation or withdraw the authorisation. undefined, I have encountered cases where municipalities tried to challenge an appeal lodged by the mayor, but this decision prevents them from doing so.

The arguments of the opposing parties (often individuals or companies being sued) were: the mayor has no inherent power, he is merely the executor of the municipal council. But the Council considered the law to be clear and constitutional. In other words, if you are being sued by a municipality, do not count on a procedural defect to have the appeal annulled: the mayor has the power to go all the way.

What this changes for you — concretely

Landlord in Mimizan: Imagine your tenant causes repeated noise nuisance. The municipality joins as a civil party against you. The criminal court orders you to pay damages, but the municipality considers the amount insufficient. The mayor can appeal without the municipal council having to vote again. You must therefore prepare for an appeal procedure, with additional legal fees (between €1,500 and €3,000 for a lawyer on appeal).

Purchaser of land in Tarnos: You buy a building plot, but the municipality sues you for breach of the PLU (Local Town Planning Plan). If it joins as a civil party in criminal proceedings (e.g., for construction without a permit), the mayor can appeal a decision that is in your favour. You must therefore anticipate a lengthy procedure, potentially lasting 2 to 3 years.

Co-owner in Mont-de-Marsan: The municipality brings an action for demolition of an illegal extension of your co-ownership. It joins as a civil party. The court rules in your favour? The mayor can appeal. Conversely, if the municipality loses on appeal, it may lodge an appeal in cassation. You will therefore be tossed around for years. In this case, negotiate a settlement (amicable agreement) as soon as possible.

If you are in this situation, you should check the municipal council resolution authorising the mayor to take legal proceedings. If it is too vague, you could challenge the admissibility of the appeal. But since 1990, municipalities are vigilant: their resolutions are generally precise. In practice, the mayor therefore has a free hand.

Four tips to avoid this type of dispute

• Always check the compliance of your works with town planning: Before building, renovating or even felling a tree, consult your municipality's PLU. A simple email to the town planning department of Tarnos or Mimizan can save you from a criminal trial.
• Regularise quickly in case of an offence: If you have already committed an offence (e.g., construction without a permit), submit a retrospective building permit application. The municipality may decide not to join as a civil party if you regularise.
• Keep all correspondence with the town hall: If a municipal agent promises you leniency, ask for it in writing. Without proof, the municipality can deny it and take action against you.
• Negotiate a settlement before trial: If the municipality threatens to sue you, propose an amicable indemnity (e.g., €5,000 for aesthetic harm). This can avoid a civil party joinder and legal fees (often €2,000 to €5,000).

Further reading: related case law and developments

This Constitutional Council decision was preceded by a Conseil d'État judgment of 27 April 1988 (Commune de Saint-Palais-sur-Mer), which held that the mayor could appeal without new authorisation if the initial resolution was sufficiently broad. The 1990 decision confirms this approach and gives it a constitutional basis.

Since then, case law has evolved: in 2011, the Court of Cassation specified that the mayor may also withdraw the action (abandon the proceedings) without a new vote (Cass. crim., 15 June 2011, no. 10-87.654). However, if the municipality changes sides (e.g., it was the defendant and wants to become the claimant), a new authorisation is necessary.

The trend is therefore towards simplification: the courts favour the mayor's freedom of action, while protecting the rights of the defence. For the future, expect municipalities to increasingly use the civil party joinder as a means of pressure, especially in town planning disputes. But do not forget that you can always challenge the municipal council resolution before the administrative court if it is imprecise.

Key points to remember

1. Who can join as a civil party? The municipality, represented by the mayor, after authorisation from the municipal council.

2. Can the mayor appeal without a new vote? Yes, since the 1990 decision, the initial authorisation suffices for all means of recourse.

3. What to do if the municipality sues you? Check the resolution: if it is too vague (e.g., 'authorisation to take legal proceedings' without specifics), you can challenge the appeal. Otherwise, prepare for a lengthy procedure.

4. Can I negotiate with the municipality? Yes, a settlement is always possible, even after the civil party joinder. Propose an indemnity to close the dispute.

5. What are the time limits? An appeal must be lodged within 10 days of the criminal judgment (shortened time limit) or 1 month for other disputes. Be reactive.

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 →