Project Manager: Their Duty to Advise Does Not Cover Compliance with Building Permits

Imagine you are a property owner in Parentis-en-Born, with that renovation project for your Landes house that you've been dreaming about for months. You've hired a project manager (the professional who designs and oversees your construction site) to assist you, obtained your building permit, and work begins. But then, during the process, you make a few changes: a larger window here, a different finish there. These changes seem minor, but they deviate from the initial permit. A year later, the town hall notifies you of an infringement and demands restoration. Who is responsible? Your project manager, who you thought was covered by their duty to advise (their professional obligation to guide and inform you), or you, the property owner?

This question is not theoretical: it arises daily in the jurisdiction of Mont-de-Marsan, where extension, renovation, or new construction projects flourish, from Mimizan to Parentis-en-Born. Property owners, often unfamiliar with the intricacies of planning law, naturally rely on the professionals they pay. But how far does the responsibility of these professionals extend?

The Cour de cassation (the highest French judicial court) answered clearly in 2009 in a decision that remains authoritative today. It ruled that the project manager's duty to advise does not oblige them to remind the client (the property owner commissioning the works) of the obligation to comply with the building permit requirements. In short, it is the property owner's responsibility to ensure their project remains within the legal framework. This distinction, subtle but crucial, changes the game for thousands of property development projects. But what exactly does this change for you, a Landes property owner or sector professional?

The Facts: A Story That Happens Every Day

Let's return to the origins of this case, which could happen today in Mimizan or any other commune in the Landes. In 1996, a property owner, let's call her Mrs. Martin for ease of narration, obtains a building permit for works on her house. She entrusts the design and oversight of the project to a project manager, Mr. Dubois, a reputable professional in the region. Work begins, but Mrs. Martin, enthusiastic, decides to make a few modifications: she enlarges a bay window and changes the location of a partition, adjustments that seem trivial to her.

Problem: these changes no longer correspond to the initial building permit. The project manager, Mr. Dubois, does not formally point out this discrepancy to Mrs. Martin. Work progresses, and it's only later that the town hall, during an inspection, notes the infringement. It refuses a request for a modified permit (an authorisation to regularise the changes) submitted after the fact, and demands restoration of the premises. Estimated cost: several tens of thousands of euros, a significant sum for a property owner.

Mrs. Martin, feeling aggrieved, then takes legal action against Mr. Dubois. Her argument: as project manager, he had a duty to advise that included alerting her to the non-compliance with the permit. She believes he failed in this obligation, thereby causing her loss. The case climbs the judicial ladder, with twists and turns: the initial judges might have ruled in favour of Mrs. Martin, considering that the professional should guide her on all aspects, including regulatory ones. But Mr. Dubois contests, arguing that his technical role does not cover the property owner's ultimate responsibility towards the authorities. The legal battle finally reaches the Cour de cassation in 2009, which will settle this emblematic dispute.

The Court's Reasoning — Analysed

The Cour de cassation, in its judgment of 14 January 2009, analysed the situation with a rigour that now illuminates the entire profession. The magistrates (the judges of this high court) recalled the legal basis: the project manager's duty to advise stems from their contract of engagement, generally governed by the MOP law (law on public project management, but whose principles also apply to the private sector) and by Articles 1101 et seq. of the Civil Code on contracts. This duty implies that the professional must inform and guide their client on the technical, economic, and legal aspects related to their engagement.

But beware: the court specified that this duty does not extend to reminding the property owner of an obligation that falls directly on them by virtue of the law. Here, the obligation to comply with building permit requirements is imposed by the planning code, notably its Articles L. 430-1 et seq. In other words, it is a legal obligation that rests on every property owner, regardless of the involvement of a project manager. The court ruled that the project manager is not required to make a systematic reminder of this rule, unless concrete elements (such as blatant modifications during construction) should normally lead them to intervene.

In this case, the judges considered that Mrs. Martin, in modifying her project, had acted on her own initiative. Mr. Dubois, even if he could observe the changes, was not required to remind her of the obligation to comply with the permit, as this primary responsibility belonged to her. The court thus confirmed prior case law that clearly distinguishes the technical role of the project manager from the legal responsibility of the property owner. This is not a reversal (a radical change of position), but an important clarification: the duty to advise has limits, and it does not cover monitoring the client's compliance with planning rules.

The parties' arguments were typical: Mrs. Martin pleaded legitimate trust in her professional, while Mr. Dubois invoked the separation of responsibilities. The court ruled in favour of the latter, emphasising that the property owner remains the primary guarantor of their project's compliance. What few people know is that this decision also protects project managers from overly extensive liability, but it imposes increased vigilance on property owners.

What This Changes for You — Practically

This decision has immediate practical implications for all property actors in the Landes and beyond. If you are a landlord (who rents out a property) or an owner-occupier, and you undertake works, you must understand that the responsibility for complying with the building permit falls primarily on you. Even with a competent project manager, as can be found in Parentis-en-Born or Mimizan, it is up to you to ensure that any modifications are regularised. Concrete example: if you enlarge a terrace without a modified permit, and the town hall demands its demolition, you will not be able to systematically turn against your project manager for compensation.

For tenants, the impact is indirect but real. If your landlord undertakes non-compliant works, this can lead to conflicts with the authorities, even work stoppages, affecting your peace. undefined, I have encountered cases where tenants in Mimizan had to endure prolonged disturbances because works were halted due to permit infringements. Regularisation delays can extend over several months, with additional costs often passed on.

For purchasers (potential buyers), this decision reinforces the importance of checking the compliance of previous works before purchase. A property that has undergone unregularised modifications may see its value decrease, and the purchaser could inherit problems with the town hall. Imagine buying a house in Parentis-en-Born for €250,000, then discovering that a 20 m² extension is non-compliant: restoration could cost €15,000 to €30,000, and the procedure could take 6 to 12 months. How to react? By demanding a certificate of compliance or having the file checked by a professional before signing.

For co-owners, the stakes are similar: common works (such as renovating a façade) must comply with the permit, and collective responsibility is engaged. If individual co-owners modify their private parts without authorisation, they risk sanctions, and the co-ownership may be involved. In all cases, this decision emphasises that everyone must be proactive in the regulatory monitoring of their project.

Four Tips to Avoid This Type of Dispute

• Establish a clear contract with your project manager: specify in writing the limits of their engagement, particularly regarding monitoring regulatory aspects. Ask them to inform you in writing of any modifications necessary to the building permit, but know that the final responsibility remains yours.
• Systematically consult the town hall before any modification: even for a minor change, like replacing a window in Mimizan, submit a request for a modified permit or a prior declaration. Response times are generally 1 to 2 months, and this avoids unpleasant surprises.
• Document all stages of your project: keep plans, exchanges with the project manager, and authorisations. In case of dispute, this evidence will be crucial to establish responsibilities, as I have seen in Landes cases where the absence of written records complicated matters.
• Consult a specialised solicitor early on: an early consultation, even for €45 as I offer, can help you structure your project and anticipate risks. This is particularly useful for complex projects, like extensions in protected zones near the Landes lakes.

In-Depth Analysis: Related Case Law and Developments

The 2009 decision fits into a jurisprudential trend (the body of court decisions) that clarifies responsibilities in construction. Before this, judgments like that of the Bordeaux Court of Appeal in 2005 had already emphasised that the project manager is not the ultimate guarantor of regulatory compliance. However, other decisions, like a Cour de cassation judgment of 2012 (No. 11-10.045), have recalled that the project manager can be liable if they commit a technical fault that directly leads to an infringement, for example by designing a plan non-compliant with planning rules.

The trend in the courts, notably in the jurisdiction of Mont-de-Marsan, is to carefully distinguish: on one hand, the legal responsibility of the property owner; on the other, the contractual responsibility of the project manager limited to their engagement. What this means for the future? Professionals will need to be even more precise in their contracts, and property owners more vigilant. With the evolution of environmental and urban standards, these issues will become even more crucial, particularly in sensitive areas like the Landes coastline.

Summary and Next Steps

To summarise, here is a numbered checklist of what to do if you are concerned:

1. Check your building permit: before starting works, ensure all plans correspond to the obtained authorisation.
2. Anticipate modifications: if you wish to change something, even small, consult the town hall or a professional to know if a new authorisation is necessary.
3. Communicate in writing: with your project manager, exchange emails or letters to track decisions, especially on regulatory aspects.
4. Monitor the construction site: as property owner, visit the site regularly to ensure works follow the permit.
5. Act quickly in case of problem: if you notice a discrepancy, regularise it immediately to limit sanctions, which can go up to €6,000 in fines and demolition.

In short, this decision makes you more responsible, but it also gives you the keys to act with full knowledge.

Do you find yourself 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 →