PLU Zoning in France: Urban, AU, Agricultural and Natural Zones Explained

Before buying land or submitting a building permit application, it is essential to know the PLU zone (zone PLU) your plot falls into. France’s local planning code — the Plan Local d’Urbanisme (PLU) — classifies every parcel of land in a municipality into four main categories: U, AU, A and N — each with its own buildability rules. Understanding PLU zoning means avoiding costly surprises and knowing exactly where you can legally build your future home.

PLU zoning: why it exists and how it works

Zoning (zonage) is the graphic translation of a municipality’s planning decisions. Every parcel of land is classified into a zone according to its intended use: urban, to-be-urbanised, agricultural or natural. Each zone has a corresponding written regulation (règlement écrit) specifying what can be built there, maximum heights, setback distances from boundaries, and so on.

Zoning is compulsorily shown on the zoning map (plan de zonage), one of the core documents of the PLU. It can be consulted at the town hall (mairie), on the municipality’s website, or on Géoportail de l’urbanisme.

Zone U: the urban zone

Zone U (urban) covers already urbanised areas and zones where existing public infrastructure has sufficient capacity to serve future buildings. It is the prime zone for construction: everything is possible in principle (subject to the written regulations).

Characteristics of zone U

• Existing utility networks: drinking water, electricity, drainage (mains or on-site)
• Existing road access
• Immediately buildable
• Variable density depending on the sub-zone

Common sub-zones within zone U

The PLU generally divides zone U into several sub-zones identified by an additional letter:

Each sub-zone has its own regulations: UA often requires street-line alignment and a minimum of four storeys, while UD imposes a 5 m setback and limits buildings to two storeys.

Zone AU: the to-be-urbanised zone

Zone AU designates areas of natural character that the municipality intends to urbanise in the future. There are two sub-types:

Zone 1AU (or “open” AU)

Peripheral public infrastructure (roads, utilities) has sufficient capacity to serve future development. The zone is immediately buildable as part of a comprehensive development operation.

Such operations are often governed by an OAP (Orientation d’Aménagement et de Programmation — a masterplan brief) defining the layout of roads, green spaces and housing types.

Zone 2AU (or “strict” AU)

Public infrastructure is insufficient: the zone is not immediately buildable. It will only become developable after a PLU modification or revision, which can take several years.

Zone A: the agricultural zone

Zone A protects agricultural land with productive potential (cultivated land, meadows, vineyards, orchards). The principle is straightforward: building in zone A is not permitted, except in specific cases.

What is permitted in zone A

• Buildings linked to agricultural operations: barns, livestock buildings, greenhouses, grain silos
• Farmer’s dwelling: provided the residence is genuinely necessary for the operation (livestock monitoring, crop surveillance)
• Agricultural diversification: rural holiday lets (gîtes), farm shops, educational farms (often managed through STECAL — see below)

What is not permitted in zone A

• Dwellings for non-farmers
• Housing developments or urban planning operations
• Commercial or industrial activities unrelated to agriculture

Zone N: the natural and forest zone

Zone N protects areas with a natural, forest, landscape or ecological character. It typically covers forests, woodlands, classified woodland areas (espaces boisés classés — EBC), wetlands, Natura 2000 sites, and river corridors.

Buildability in zone N

As with zone A, the default position is no building. A few exceptions apply:

• Limited extensions to existing buildings (generally capped at 30% of the original floor area)
• Outbuildings attached to existing buildings (garden sheds, garages)
• Buildings required for public services or community facilities
• Buildings linked to forestry operations

STECAL provisions in zones A and N

A STECAL (Secteur de Taille Et de Capacité d’Accueil Limitées — a small-scale, limited-capacity exception sector) is a mechanism that allows, on an exceptional basis and within defined boundaries, certain buildings that would not normally be permitted in zone A or N. Examples include:

• Existing hamlets in rural areas earmarked for slight densification
• One-off tourism projects (campsites, holiday lets)
• Specific activities (equestrian centres, farm restaurants)

STECAL provisions are defined by the municipality in its PLU and remain uncommon.

How to find a plot’s zone

To identify the PLU zone of a parcel:

1. Online: go to geoportail-urbanisme.gouv.fr, search for the municipality and click on the parcel. The zone is displayed immediately.
2. At the town hall: ask to consult the PLU zoning map and the written regulations for the relevant zone.
3. On the municipality’s website: most municipalities publish their full PLU (map + regulations) as a downloadable document.
4. Planning certificate (certificat d’urbanisme): for an official and legally binding answer, apply for a planning certificate (certificat d’urbanisme) at the town hall.

Reading the zone’s written regulations

Once the zone is identified, you need to read the corresponding written regulations (règlement écrit). These are structured as numbered articles, the main ones being:

The mandatory dimensions derived from these articles are detailed in our guide regulatory dimensions on a building plan.

Zoning pitfalls to avoid

The “split-zone” plot

A parcel can straddle two zones (for example UB and N). In that case, each part is governed by its own regulations. Your buildable area is reduced to the portion in zone U, which may make the project unviable.

Reserved plots (emplacements réservés)

The PLU may designate a reserved plot (emplacement réservé) on your parcel for a public interest project (road widening, public facility). You cannot build on that portion. These are shown on the zoning map.

Public utility easements (servitudes d’utilité publique)

These are independent of the PLU but overlay it: high-voltage power lines, gas pipelines, listed historic monuments, classified sites. They can make a plot unbuildable even when it is in zone U.

A PLU under revision

If the municipality has initiated a PLU revision, the current zoning may change. Ask the town hall how far the process has progressed and whether your parcel is affected.

For further preparation, see also our guides on PLU: how to consult it before building and building permit vs prior declaration.