What does a construction without a permit or non-compliant risk?

Guide led by Arthur Merlino, founder of BRIVEOReviewed by the Briveo teamUpdated on July 17, 2026

Building without a permit is an offence punishable by a fine (article L.480-4 of the French Town Planning Code), which prosecution bars after six full years (article 8 of the French Code of Criminal Procedure). The ten-year administrative limitation (article L.421-9 of the French Town Planning Code) does not benefit constructions built with no permit at all where one was required.

The criminal offence and its six-year limitation

Carrying out works without the required authorisation, or in breach of the one obtained, is an offence punished by article L.480-4 of the French Town Planning Code. The fine ranges from 1,200 € up to an amount which cannot exceed, where a floor area is built, 6,000 € per square metre of surface built, demolished or rendered unusable and, in other cases, 300,000 €. In the event of a repeat offence, a prison sentence of six months may also be handed down.

The public prosecution of offences of this class is time-barred after six full years from the day the offence was committed (article 8 of the French Code of Criminal Procedure, as worded following the law of 27 February 2017 reforming limitation in criminal matters). For an unlawful construction, the French Court of Cassation sets this starting point at the completion of the works, that is the day the structure is in a state to be put to the use for which it is intended (Court of Cassation, criminal division, 27 May 2014, no. 13-80.574). Once this period has passed, criminal proceedings are no longer possible, but this limitation erases neither the unlawfulness of the construction nor the other civil or administrative consequences.

The ten-year administrative limitation and its limits

On the administrative side, a distinct rule applies. Where a construction has been completed for more than ten years, a refusal of a building permit or a decision of opposition to a prior declaration can in principle no longer be based on the unlawfulness of the initial construction under town planning law (article L.421-9 of the French Town Planning Code). A later regularisation is thereby made easier.

This ten-year limitation nonetheless has exceptions listed exhaustively by article L.421-9. In particular, it does not apply where the construction was built without any building permit having been obtained when one was required, where it is located in a national park, a listed site, or on the public domain, where an action for demolition has been brought, or where it exposes its users or third parties to a risk of death or serious injury. A construction built with no permit at all is thus expressly denied the benefit of the limitation: the unlawfulness can then be relied upon without the ten-year period standing in the way.

Regularise or risk demolition

An unlawful construction can often be regularised by filing a building permit or a prior declaration after the fact, if the project complies with the town planning rules in force at the time of the application. The town hall then assesses the application as it would for a new construction.

Failing regularisation, the court that hands down a conviction on the basis of article L.480-4 rules, in light of the observations of the competent authority, on bringing the site into compliance or on demolishing the works (article L.480-5 of the French Town Planning Code). A civil action for demolition also exists, but article L.480-13 reserves it for the case of a permit previously annulled for excess of power (exces de pouvoir), in exhaustively listed zones and within two years of the decision becoming final. Finally, an unregularised construction weakens any future sale, since the seller must inform the buyer of the situation.

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Frequently asked questions

Can you regularise a construction built without a permit?

Yes, by filing a building permit or a prior declaration after the fact, provided the construction complies with the town planning rules applicable at the time of the application. Regularisation does not make the criminal offence already committed disappear, but it clears up the administrative situation.

After how long is an unlawful construction protected?

The public prosecution is time-barred after six full years, the French Court of Cassation running this period from the completion of the works. On the administrative side, once ten years have passed the initial unlawfulness can in principle no longer ground a refusal, but article L.421-9 of the French Town Planning Code excludes this benefit in several cases, notably where the construction was built with no permit at all when one was required, or where it lies on a listed site or on the public domain.

Can a neighbour have an unlawful construction demolished?

Article L.480-13 of the French Town Planning Code covers only the case of a permit annulled for excess of power: demolition then presupposes that the construction lies in one of the exhaustively listed zones and that the action is brought within two years of the decision becoming final. A construction built with no permit at all falls outside this provision; the neighbour must then act on another basis, for example abnormal neighbourhood disturbance (article 1253 of the French Civil Code).

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