France's Coastal Law: buying by the sea, the 100 m strip

Which communes are affected?

Article L321-2 of the code de l’environnement (Environment Code) defines the communes littorales (coastal municipalities) of mainland France and the overseas départements:

• communes bordering seas and oceans, saltwater lagoons and inland bodies of water of more than 1,000 hectares;
• communes bordering estuaries and deltas, located downstream of the saltwater limit, listed by a decree of the Conseil d’État (the highest administrative court).

Planning documents (SCoT, the area-wide planning scheme; PLU, the local development plan; carte communale, the simplified municipal map) must be compatible with the Act, and its provisions also apply directly to individual permits, except where a directive territoriale d’aménagement (regional planning directive) exists. Since the loi ELAN of 23 November 2018, it is the SCoT that specifies how it applies locally (Ministry of Regional Planning). In other words, the same rule may be applied differently from one commune to another: reading the PLU and the SCoT is essential.

Three levels of protection according to distance from the shore

Source: Ministry of Regional Planning. The Act also requires green breaks between built-up areas and the protection of outstanding natural areas, where only very light facilities are allowed.

The 100-metre strip in detail

The strip is measured from the upper limit of the shore, i.e. the limit of the highest tides excluding exceptional weather disturbances, or from the highest water level for a lake of more than 1,000 hectares. The distance is calculated horizontally, regardless of terrain or obstacles. 100 metres is a minimum: the PLU may extend it (code de l’urbanisme, the Planning Code, art. L121-19) (DGALN technical sheet, June 2021).

In the non-built-up areas of the strip, the principle that land is unbuildable (art. L121-16) applies to:

• new buildings;
• extensions to existing buildings (Conseil d’État, 21 May 2008);
• changes of use (Conseil d’État, 8 October 2008).

Only strengthening works are allowed, with a few exceptions listed exhaustively: facilities needed for public services or for economic activities requiring immediate proximity to the water (fishing, marine farming, port activities), subject to a public inquiry. Case law excludes restaurants, thalassotherapy, car parks and housing (Conseil d’État, 8 March 2004). The courts also apply this rule to certificats d’urbanisme (planning certificates) (Conseil d’État, 10 November 2004).

What this means for a buyer: a house in the non-built-up part of the strip may be maintained, but not enlarged or converted. A bare plot there is in principle unbuildable.

Overseas, the 100-metre strip does not apply in Guadeloupe, French Guiana, Martinique, La Réunion and Mayotte: the regime of the strip known as the cinquante pas géométriques (fifty geometric paces) (art. L121-45 to L121-49) applies there instead (DGALN sheet). The parts of this zone that have not been sold off belong to the domaine public maritime (public maritime domain) (Ministry of Ecological Transition).

The public footpath easement

Since the Act of 31 December 1976, a public footpath easement along the coast, known as the servitude EL9, has applied over a 3-metre strip from the limit of the highest astronomical tides, and in the fifty geometric paces zone overseas. The path is for pedestrians only; the easement may be suspended or altered following a public inquiry (GéoLittoral, updated on 2 June 2025).

In 2019, 5,350 km of path were open in mainland France and Corsica, of which 1,420 km under this easement, and 450 km overseas, of which 105 km under the easement. A seafront property may therefore have a public path running alongside or across it: it is best to locate it before buying, for example on the coastal path mapping portal published by GéoLittoral.

Coastal risks to check

An area exposed to coastal retreat, mapped by a PLU, a carte communale or a provisional map, is one of the zones where the état des risques (risk report) is compulsory, in the same way as risk prevention plans (service-public.gouv.fr, checked on 28 September 2026). For a seafront property, read the risk report carefully: see our guide on the état des risques (ERP) (risk report).

Which professional to consult

The géomètre-expert (chartered surveyor) locates the plot in relation to the shoreline and the 100-metre strip. The notaire (notary) identifies the easements burdening the property, including the public footpath easement. The agent immobilier (estate agent) can tell you, from the viewing onwards, whether the property is in an area close to the shore and what the PLU allows there.