Planning Certificate in France: What It Is and How to Get One

Before buying land or launching your house-building project, the planning certificate (certificat d’urbanisme) is the most effective tool to officially verify what you can do with your plot. A free document, legally binding on the commune, it freezes planning rules for 18 months and protects you against any PLU revision. Here is how to request it, which type to choose, and how to use it intelligently.

What is a planning certificate?

The planning certificate (certificat d’urbanisme, often abbreviated CU) is an administrative document issued by the town hall (mairie) that informs you about the planning rules applicable to a given plot. It sets out:

• Planning provisions: PLU (local urban plan) zone, constructibility rules, maximum heights, ground coverage
• Administrative limitations on property rights: public utility easements (servitudes d’utilite publique), right of pre-emption (droit de preemption), reserved zoning areas (emplacements reserves)
• Planning taxes and contributions applicable (development tax / taxe d’amenagement, etc.)
• The tax regime for any capital gains

Important: a CU is not a building authorisation. It is purely an information document. To build, you will then need to submit a building permit (permis de construire) or a prior declaration of works (declaration prealable de travaux).

The two types of planning certificate

There are two versions of the CU, and choosing the right one will save you time.

The information planning certificate (CU a)

The information CU, also called CU a, is the simpler one. It gives you a general snapshot of the rules applicable to the plot:

• Planning rules (zone, regulations)
• Administrative limitations (easements, pre-emption rights)
• Planning taxes

This is the right choice when you are exploring a plot: you want to know whether it is in zone U, AU, A or N, check for any easements, and get an idea of the rules. You do not yet have a specific project in mind.

Processing time: 1 month.

The operational planning certificate (CU b)

The operational CU, or CU b, goes much further. In addition to the information in the CU a, it tells you whether your specific project is feasible on the plot. To obtain it, you must describe your project (type, intended use, ground floor area, floor area) and provide a location plan and a brief description.

The town hall then gives a concrete answer: “yes, your project for a 120 m² house with garage is feasible” or “no, because of such-and-such rule”. The answer is legally binding: the commune cannot retract it for 18 months.

Processing time: 2 months.

CU a or CU b: which one to choose?

How to request a planning certificate

The process is simple, free, and accessible to anyone (even non-owners of the plot).

Step 1 — Fill in the Cerfa form

The form to use is Cerfa no. 13410*10 (common to both types of CU). It can be downloaded free of charge from service-public.fr.

You will need to fill in:

• Your contact details (name, address)
• The owner’s identity if different
• The address and cadastral references of the plot (section + cadastral parcel number)
• The type of CU requested: box “a” (information) or box “b” (operational)
• For a CU b: a brief description of the project (type, intended use, ground floor area, floor area, location on the plot)

Step 2 — Attach the required documents

For a CU a:

• Location plan of the plot (cadastral extract or IGN map with the plot circled)

For a CU b, in addition:

• Project description note (a few lines are sufficient)
• Plot plan showing the intended position of the buildings
• Optionally a basic massing plan if the project is complex

Step 3 — Submit the application

Three options:

1. At the town hall (mairie): hand delivery in exchange for a receipt (the safest option to have proof of date)
2. By registered post with acknowledgement of receipt
3. Online: most communes now accept digital submissions via the Guichet Unique de l’Urbanisme (GUU — single planning portal). Check with your town hall or via service-public.fr.

The receipt gives you the submission date and registration number, which is the starting point for the processing deadline.

Step 4 — Wait for the response

If the town hall does not respond within the deadline, the CU is considered tacitly issued: you can request a non-objection certificate. The content is then limited to your initial application (note: silence does not constitute approval of the project for a CU b, only of the applicable rules).

Validity of the planning certificate

This is one of the most important — and most misunderstood — points.

18 months of frozen rules

Once issued, the CU freezes for 18 months the planning rules, taxes and administrative limitations applicable to the plot. In practice, if the commune revises its PLU during those 18 months, the rules set out in the CU apply to your project, not the new ones. This is a golden guarantee for a self-builder.

Extension possible

At the end of the 18 months, you can request a one-year extension (renewable several times) provided the rules have not changed. The request must be submitted at least 2 months before expiry.

Practical implications

• Buy your plot within the 18 months following the issue of the CU to benefit from the frozen rules
• Submit your building permit during the same period
• Keep a copy of the CU with all project documents — it is a document required when applying for a mortgage and at the notary

Reading a planning certificate correctly

When you receive the CU, take the time to read it in full. Here are the priority points to check.

The zoning

The CU mentions the PLU zone of the plot (U, AU, A, N) and any sub-zones (UA, UB, etc.). This is the key piece of information: if you are in zone A or N, do not waste your time. To understand what these zones mean, consult our guide on PLU zoning and its U, AU, A, N zones.

Easements and limitations

Look for the mention of public utility easements: high-voltage lines, gas pipelines, historic monuments, water catchment perimeters. These easements can make the plot unbuildable even in zone U.

Also check whether the commune holds an urban pre-emption right (DPU), which allows it to buy back the plot as a priority at the proposed price (this does not prevent the sale, but introduces an extra step).

Reserved zoning areas

The CU indicates whether part of the plot is subject to a reserved zoning area (emplacement reserve) (road widening, future public facility). On that portion, you cannot build anything — and the commune may one day expropriate it.

Taxes

The CU details the applicable planning taxes: development tax (taxe d’amenagement) (communal + departmental share, and regional share in Ile-de-France), various contributions. This gives you a numerical estimate to incorporate into your overall budget.

For a CU b: the response to the project

In a CU b, the town hall explicitly states whether the described project is feasible or not, and sets out any conditions or refusals. A negative response must be reasoned: the commune must cite the exact rule that stands in the way of the project.

Common traps to avoid

Confusing the CU with a building permit

The CU is never a building authorisation. Even a favourable CU b does not remove the requirement to submit a building permit (permis de construire) or a prior declaration of works. To understand the difference, consult our guide building permit vs prior declaration of works.

Believing the CU guarantees technical feasibility

The CU informs you about planning rules, not the technical feasibility of the land. It says nothing about soil type, bearing capacity, the risk of special foundations, utility connections or actual slope. For these questions, plan for a G2 soil survey (etude de sol G2) and have a groundworks specialist visit the site.

Requesting a CU a when a CU b would be more useful

Many prospective self-builders default to requesting a CU a out of fear of the complexity of the CU b. But if you already have a clear idea of your house, the CU b gives you a legally binding answer about your project. It is one extra month of processing, but it allows you to invest with complete peace of mind.

Not checking the documents attached to the CU

The CU is often accompanied by an annexe plan locating the easements and reserved zoning areas on the plot. Read it carefully: it is this plan that reveals constraints that are invisible in the main text.

Buying a plot without a recent CU

A CU issued more than 18 months ago without an extension no longer protects you. If the seller provides you with an old CU, request a new one in your name: it is free and essential.

Cost and process: quick summary

To go further in your preparation, also consult our guides PLU: how to read it before you build and zoning and setback rules.