Amending building permit and regularisation during proceedings (Art. L. 600-5-1 French Town Planning Code): curing the defect rather than suffering annulment

A third-party challenge to a building permit is no longer decided solely on the lawfulness of the original permit. Now that a stay of proceedings has become the rule, the real question facing the permit holder is operational: can the defect raised by the claimant be cured, within what period, by what instrument, and at what carrying cost. For an investor bearing financing costs, a marketing timetable and sometimes a completion guarantee (garantie financière d'achèvement), the choice between defending the lawfulness of the original permit and filing an amending building permit to regularise it is worth several months of cash flow. This guide treats Article L. 600-5-1 of the French Town Planning Code (Code de l'urbanisme) as a defensive tool: which defects can be regularised, which instrument reopens the period for third-party challenges, and at what precise point in the procedural timetable the decision must be made.

What Article L. 600-5-1 of the French Town Planning Code requires of the judge

Introduced by Order No. 2013-638 of 18 July 2013 on town planning litigation, Article L. 600-5-1 was rewritten by Article 80 of Law No. 2018-1021 of 23 November 2018 on housing, development and digital technology (ELAN Law). The change is decisive: the power to stay proceedings has become an obligation.

Without prejudice to the application of Article L. 600-5, where the administrative court, seised of claims directed against a building, demolition or development permit or against a decision not to object to a prior declaration, considers, having found that the other grounds are unfounded, that a defect rendering that act unlawful is capable of being regularised, it shall stay proceedings, after inviting the parties to submit their observations, until the expiry of the period it sets for that regularisation, even after completion of the works.

Three practical consequences follow. First, the judge can no longer pronounce a straightforward annulment without having examined whether the defect found can be regularised; a refusal to grant a request for a stay must be reasoned, which gives rise to a ground of appeal on points of law (cassation). Second, the stay is ordered after all the other grounds have been dismissed: the interlocutory judgment clears the dispute of its other complaints and focuses the debate on one identified point. Finally, regularisation remains possible even after completion of the works, which is aimed directly at projects delivered and in use while proceedings are pending.

Not to be confused: L. 600-5, L. 600-5-1 and L. 600-5-2

These three articles form a system but follow distinct logics. Article L. 600-5 allows the judge to limit the annulment to the defective part of the project alone where the defect affects only a severable part of the building, and to set a period for regularisation. Article L. 600-5-1 annuls nothing: it suspends the course of the judgment to give the applicant time to produce a regularisation measure. Article L. 600-5-2, created by the ELAN Law, locks in the procedural effect of that measure:

Where an amending permit, an amending decision or a regularisation measure is issued during proceedings concerning a challenge to the permit (...) originally issued, and that permit, decision or measure has been communicated to the parties to those proceedings, the lawfulness of that act may be challenged by the parties only within those same proceedings.

In other words, the amending permit obtained during the proceedings and duly communicated cannot be attacked by a second challenge before another panel. This is the procedural counterpart of the mechanism, and the investor's main gain: a single front and a single timetable.

Mapping the defect before choosing a line of defence

Regularisation is not decided on the basis of the originating application. It is decided on the basis of the grounds that are actually effective, once the case has been investigated. The first task of the defence is to sort the complaints into those that will fail, those that can be regularised and those that cannot.

Defects of form and procedure

These are the most frequently regularisable, because in principle it is enough to redo the defective stage of the procedure without restarting the full investigation. This category includes failure to consult the architect of the Bâtiments de France (French heritage architect) in the vicinity of a listed monument, absence or inadequacy of the opinion of the environmental authority, an application file that is incomplete in light of the documents required by Articles R. 431-4 et seq. of the French Town Planning Code, an inadequate landscape statement or defective reasoning for a derogation granted. Lack of competence of the author of the act can also be regularised by a confirming decision issued by the competent authority.

Substantive defects arising from the planning regulations

Regularisation here is material: it requires the project to be modified to bring it into compliance. A height limit exceeded and corrected by removing an attic level, an insufficient setback from the boundary, a number of parking spaces below the ratio required by the local urban plan (plan local d'urbanisme), a biotope coefficient or an area of deep-soil green space not achieved, a non-compliant fire service access: each of these complaints is dealt with by an amending building permit, provided the correction remains compatible with the economic balance of the project. This is precisely where the investor's trade-off lies: curing the defect may cost saleable square metres.

Defects that cannot be regularised

Some complaints cannot be remedied. Land classified as a natural or non-developable zone, a non-building easement arising from a risk prevention plan, a direct incompatibility with the use authorised by the zoning regulations, or the unlawfulness of a decision that affects the very nature of the project leave no room for manoeuvre. In these cases, a stay serves no purpose and the strategy shifts to contesting the grounds and, where appropriate, to abandoning the project as designed and redeploying onto an alternative scheme.

Under which rules is regularisation assessed

A technical point often overlooked: the regularisation measure is assessed against the planning rules in force on the date it is issued, not on the date of the original permit. An amendment to the local urban plan made while proceedings are pending can therefore make regularisation more restrictive, or even impossible, even though the original permit complied when it was issued. This risk calls for monitoring the revision and amendment procedures of the municipal planning document throughout the litigation, and for accelerating the filing of the amending permit where an unfavourable change is under way. The stay imposed by the authority on a permit application, which is distinct from the one ordered by the judge, is analysed in our article on the stay under Article L. 424-1 of the French Town Planning Code.

A frequent misreading of Article L. 600-2 of the French Town Planning Code should also be avoided: that provision allows an application to be confirmed within six months of the final annulment of a refusal of authorisation, under the rules applicable on the date of the annulled decision. It does not protect the holder of an annulled permit. Suffering the annulment of a building permit therefore means reapplying under the rules of the day, without crystallisation.

Choosing the right vehicle: amending permit, amending decision or new permit

An amending building permit under ordinary law is subject to two classic conditions: it can be issued only while the original permit is valid and the building is not completed, and it must not call into question the overall design of the project. Outside those limits, the authority must issue a new permit subject to a full investigation.

Within the framework of Article L. 600-5-1, administrative case law has relaxed this framework. It is now accepted that the regularisation measure may take the form of an amending permit even where it substantially modifies the project, provided the applicable rules have been complied with and third parties have been able to submit their observations where the procedure required it. It is also accepted that regularisation may take place after completion of the works, as the text expressly provides. This flexibility is the most useful contribution of the mechanism for projects already delivered, in particular where a challenge has been brought late, within the six-month period following completion provided for by Article R. 600-3.

Three vehicles therefore coexist:

• the amending permit, where the correction relates to the content of the authorised project;
• the amending or confirming decision, where the defect affects the competence, the reasoning or a requirement of the permit;
• the resumption of a procedural stage, where the defect stems from an omitted or irregular consultation, followed by a regularisation decision.

The decision timetable: where the decision points lie

Regularising a building permit plays out along a timeline in which each stage opens or closes an option.

Before any challenge: securing the display and the starting point of the period

The period for third-party challenges to a building permit runs, under Article R. 600-2 of the French Town Planning Code, from the first day of a continuous period of two months of display on the site. Proof of that continuous display, in accordance with the regulatory particulars, determines everything that follows. A report by a commissaire de justice (bailiff) at the beginning, middle and end of the period remains the only evidence that is truly enforceable. Defective display leaves the permit open to challenge well beyond the theoretical period, subject only to the six-month time bar after completion provided for by Article R. 600-3. This point is dealt with in detail in our discussion of the challenge of a building permit by a third party.

The claimant is required, under Article R. 600-1, to notify the challenge to the author of the decision and to its beneficiary within fifteen clear days of filing, on pain of inadmissibility. This is the first filter to check before anything else.

Within three months of issue: the withdrawal window and the spontaneous amending permit

Article L. 424-5 of the French Town Planning Code allows an unlawful permit to be withdrawn within three months of its issue. That window is also the one in which a prudent applicant, alerted by a documented informal appeal (recours gracieux), can spontaneously file a corrective amending permit before any application to the court. Regularising upstream costs less than regularising under an interlocutory judgment, and deprives the claimant of most of its negotiating leverage.

At the stage of the defence statement: requesting the stay in the alternative

The request to apply Article L. 600-5-1 must be made in the first defence statement, in the alternative, identifying the defects the beneficiary considers itself able to cure. There are two reasons for this. First, the judge may apply the article of his or her own motion, but a reasoned request guides the analysis and lays the ground for a possible appeal on points of law in the event of an unreasoned refusal. Second, communication of the first defence statement starts the period for crystallisation of grounds under Article R. 600-5, after which no new ground may be raised. The scope of the risk then becomes known, which makes it possible to cost the regularisation.

That same crystallisation governs the admissibility of the application for a suspension in summary proceedings (référé-suspension): Article L. 600-3 reserves the application for suspension to the period before the crystallisation period expires. Beyond that point, the site is no longer exposed to an urgent suspension. The same procedure, seen from the claimant's side, is examined in our article on the offensive strategy of the investor challenging a permit.

During the period set by the judge: investigating and issuing

The interlocutory judgment identifies the defect and sets the period for regularisation. That period runs over the full administrative investigation of the amending permit, including, where applicable, the omitted consultation, the making available to the public or the opinion of the environmental authority. The point of tension is logistical as much as legal: the amending permit file must have been prepared before the judgment, not after, failing which an extension must be requested that the judge is not obliged to grant.

After issue: notifying the court and closing the litigation

The regularisation measure must be notified to the court and communicated to the parties. The proceedings resume, the parties are invited to submit their observations, and the claimant may no longer direct grounds against the original permit except within the limit of what remains. If the defect is cured, the challenge is dismissed and the original permit, supplemented by the amending permit, leaves the litigation for good.

Which instrument reopens a period for third-party challenges

This is the question that often decides the strategy, because a poorly sequenced amending permit can restart the litigation instead of ending it.

An amending building permit issued outside any proceedings is an autonomous decision, open to challenge under ordinary conditions: display on the site, a two-month period, notification of the challenge under Article R. 600-1. The challenge may, however, relate only to the elements the amending permit modifies or to defects specific to it. An original permit that has become final does not become open to challenge again because an amending permit is issued. This rule protects the investor, provided the amending permit stays within the limits of an amendment and cannot be characterised as a new permit for a substantially different project, in which case the act can be challenged in its entirety. The standing of third parties, the starting point of their period and the absence of suspensive effect are set out in our article on third-party challenges to a building permit.

An amending permit issued during proceedings and communicated to the parties falls under Article L. 600-5-2: its lawfulness may be discussed only in the pending proceedings. The communication requirement is substantive. A regularisation measure that has been issued but not placed before the adversarial debate does not benefit from this lock and remains exposed to an autonomous challenge. The procedural discipline is simple: file the amending permit in the case, request its formal communication to the parties, and have the resumption of the investigation recorded.

Two time limits finally frame the whole:

• Article R. 600-3 makes inadmissible any application for annulment brought more than six months after completion of the building, the date of completion being established by the declaration certifying completion and compliance of the works;
• the authority's challenge to compliance is confined within the verification periods (récolement), three months from the completion declaration, extended to five months where verification is mandatory.

Economic effects: validity of the permit, financing, condition precedent

The litigation does not use up the validity period of the permit. Article R. 424-19 of the French Town Planning Code suspends the validity period, set at three years by Article R. 424-17, until an irrevocable court decision is delivered. A prolonged stay of proceedings therefore does not cause the permit to be lost. It remains that suspension is not extension: applications for extension follow their own regime, set out in our guide on extending a building permit, and must be anticipated where the operational timetable slips for reasons unrelated to the litigation.

On the acquisition side, Article L. 600-5-1 shifts the content of conditions precedent. The classic clause providing for a permit free of any challenge and any withdrawal remains the reference, but it must be supplemented. A transaction under an interlocutory judgment is neither cleared nor condemned: it is in an intermediate state that the clause must address, for example by distinguishing between the challenge pending on the merits, the stay ordered, and the issue of the regularisation measure. The questions of the transfer of litigation risk, the bearing of regularisation costs and the revision of the price in the event of a loss of floor area must be settled in the preliminary agreement (promesse), not at completion. We deal with this mechanism in our discussion of acquisition subject to a condition of a permit free of challenge.

Finally, the abusive use of a challenge remains punishable. Article L. 600-7 of the French Town Planning Code allows the permit holder to claim damages where the challenge exceeds the defence of the claimant's legitimate interests and causes excessive harm, and Article L. 600-8 regulates settlements by providing for their registration, on pain of nullity, where they include a financial consideration for the withdrawal of the claim. Article R. 600-6 also requires the judge to rule within ten months on challenges directed against permits for a building comprising more than two dwellings and against development permits for a subdivision, which reduces the nuisance value of a dilatory challenge.

Conclusion

The choice is not between defending and regularising: it is between regularising early, under control, and regularising late, under the constraint of the judge and the financial timetable. The mechanism of Article L. 600-5-1 of the French Town Planning Code has shifted the burden of risk in favour of the project promoter, but it benefits only well-prepared cases: probative display, a mapping of defects drawn up from the defence statement onwards, an amending permit file ready before the interlocutory judgment, and an irreproachable communication of the regularisation measure to the parties so as to close the second front by the effect of Article L. 600-5-2.

The operational recommendation fits in one sentence: on receipt of the notification of a challenge under Article R. 600-1, have two analyses prepared in parallel, one on the admissibility and merits of the grounds, the other on the cost and technical feasibility of an amending building permit to regularise. Choosing a strategy without having costed the second amounts to letting the claimant set the timetable of your project.

Frequently asked questions

Can the judge refuse to stay proceedings where a defect can be regularised? Since the ELAN Law of 23 November 2018, a stay is the rule: a judge who finds, having dismissed the other grounds, that a defect is capable of being regularised must stay proceedings. Article L. 600-5-1 of the French Town Planning Code expressly requires that a refusal to grant a request for a stay be reasoned. An unreasoned or insufficiently reasoned refusal is a useful ground on appeal and on a point of law.

Is an amending permit possible after completion of the works? An amending permit under ordinary law presupposes that the building is not completed. Article L. 600-5-1 derogates from that rule: it authorises regularisation even after completion of the works. This is a frequent scenario where the challenge was brought late, Article R. 600-3 admitting challenges within six months of completion of the building.

Does the amending permit reopen the period for challenging the original permit? No. An original permit that has become final does not become open to challenge again because an amending permit is issued. Third parties may challenge only the modified elements or the amending permit's own defects, within the two-month period running from its display on the site under Article R. 600-2. The solution differs if the act, by its scale, is in reality a new permit.

What period does the judge set for regularisation? The text leaves the judge free: the period is set in the interlocutory judgment, having regard to the nature of the defect and the administrative procedure to be resumed. A defect of form is cured more quickly than a change to the project requiring a new consultation or an environmental assessment. The amending permit file must therefore be prepared before the judgment, not after.

Is regularisation assessed against the local urban plan applicable to the original permit? No, the regularisation measure is in principle examined against the planning rules in force on the date it is issued. A revision or amendment of the local urban plan made while proceedings are pending can therefore tighten the conditions of regularisation. The procedures for changing the municipal planning document must be monitored throughout the litigation.

Does a challenge to the permit cause it to lose its validity period? No. Article R. 424-19 of the French Town Planning Code suspends the three-year validity period provided for by Article R. 424-17 until an irrevocable court decision is delivered. A prolonged stay of proceedings therefore does not use up the permit, but the suspension does not remove the need to anticipate an application for extension where the delay stems from causes unrelated to the litigation.

What happens if the amending permit is not communicated to the parties? Article L. 600-5-2 applies only if the regularisation measure has been communicated to the parties to the proceedings. Otherwise, the amending permit remains exposed to an autonomous challenge before another panel, which reopens a second front of litigation and a new timetable. Filing the amending permit in the case and communicating it formally are therefore acts of procedural strategy, not mere formalities.