The period of validity
The permit lapses by operation of law if the holder has not begun carrying out the works to a significant extent within two years of obtaining it.
Lapse operates by law, meaning it requires neither decision nor notification. It is simply established.
The consequence is drastic: resuming the project requires a fresh application, processed against the rules in force at that time, which may have changed.
| Notion | What it covers | Point to watch |
|---|---|---|
| Validity period | How long the permit remains usable | It runs from issue |
| Start of works | What interrupts lapse | The notion is not defined uniformly |
| Extension | The prolongation of the period | It is requested before expiry |
What beginning works means
A matter of judgment deserving caution.
The text requires that carrying out has begun to a significant extent, which excludes token starts.
This notion is assessed case by case, and there is no list of sufficient acts.
A start intended solely to interrupt the period is therefore risky, since it may be judged not significant.
The prudent rule: start a real site or apply for an extension, rather than relying on a token beginning.
The extension mechanism
Four elements, all to be known before the period expires. They condition the extension of the permit.
The mayor may grant an extension of the lapse period.
Its maximum duration is one year.
It requires a written and reasoned application from the holder of the permit.
It is not available as of right. It is a discretion, and the reasoning matters.
The application must be made before the period expires, a permit that has already lapsed no longer being capable of extension.
The situations at risk
Five situations where the period becomes a real issue. They concern financing, appeals and contractors.
A third-party appeal, which freezes the project while the period continues to run.
Financing not finalised, which delays the start without suspending the period.
Awaiting another permit, notably a State or sectoral one.
An unsuccessful tender, where the offers received exceed the budget and force the project to be reworked.
Land acquired ahead of a deferred project, a frequent case where the permit is obtained early to secure developability.
In these five cases, an extension is prepared, not improvised.
The interaction with the appeal period
A programming point that surprises.
The lapse period runs from obtaining the permit, not from expiry of the appeal period.
The two periods therefore overlap. The three months of appeal consume part of the two-year period.
Awaiting expiry of the appeal period before starting works is prudent, but it reduces the margin before lapse accordingly.
This overlap must appear in the programme, as the article on the timeline of a project explains.
What this means for a professional
Four rules.
Note the expiry date on issue, and enter it in the project programme.
Alert the client several months before expiry, extension requiring a reasoned application.
Do not advise a token start, whose significance may be contested.
Recall that a fresh application will be processed against the rules then in force, which may be less favourable.
This article reflects the regulatory framework at the date of checking and serves professional orientation. It does not replace consultation of the municipality or legal advice.