Party walls in France: presumption, costs, buying in

When is a wall a party wall?

The presumption. In towns as in the countryside, walls separating buildings up to the height of the lower building (jusqu’à l’héberge), yards and gardens, and even enclosures in fields, are presumed to be party walls (murs mitoyens) (art. 653). The presumption falls if there is a title or a mark to the contrary.

Marks showing the wall is not shared (art. 654):

• a top that is straight and vertical on one side and sloping on the other;
• a coping (chaperon), or stone ledges and corbels (filets et corbeaux de pierre), on one side only.

The wall then belongs solely to the owner on the side where the drip edge or the stone corbels and ledges are (art. 654). A wall may be a party wall for only part of its length (service-public.gouv.fr, fact sheet F2415).

Proof. Service-public.gouv.fr cites the title deed, an agreement between neighbours published in the land register (fichier immobilier) and thirty years’ possession (possession trentenaire), for example a building resting against the wall for more than 30 years, with possession that is continuous, peaceful, public and unequivocal (F2415). The limitation period for acquiring ownership of real property is thirty years, reduced to ten years for someone who acquires in good faith and with a valid title (juste titre) (art. 2272).

Maintenance, repairs and rebuilding: who pays?

Giving up the party wall. A co-owner can avoid contributing to repairs and rebuilding by giving up their right, provided the wall does not support a building belonging to them (art. 656). Service-public.gouv.fr adds two points: the wall must not hold back soil (a retaining wall, mur de soutènement), and the neighbour must first repair any damage caused by their own lack of maintenance. The surrender is announced by registered letter and formalised by a private agreement or a notarial deed (acte sous seing privé ou acte notarié). The person giving it up loses ownership of the land under the wall and the right to rest a building against it (F2415).

Buying a share in a wall

“Any owner whose land adjoins a wall has the option of making it a party wall in whole or in part” (art. 661). The price comprises:

• half the cost of the wall, or of the portion of wall concerned;
• half the value of the land on which it is built.

The cost is estimated at the date of acquisition, taking into account the condition of the wall (art. 661). According to service-public.gouv.fr, the purchase only applies to a wall built on the boundary line: a wall that extends onto the neighbouring land is an encroachment (empiètement) and cannot become a party wall. The neighbour is informed by registered letter and the deed is drawn up by a notaire (notary) (F2415).

Can the wall’s owner refuse? Service-public.gouv.fr states that “The neighbour may refuse to sell their share” (F2415). The Civil Code, on the contrary, presents the acquisition as an option for the owner whose land adjoins the wall, without making it subject to the owner’s agreement (art. 661). It reserves the ban on forcing a sale to non-shared ditches and hedges (art. 668). In the event of disagreement, it is the text of article 661 that the judge applies.

Building against, cutting into, raising: works on a party wall

Building against the wall. Each co-owner may build against a party wall and insert beams or joists through the full thickness of the wall, less fifty-four millimetres. The neighbour may have the beam cut back to the middle of the wall in order to set their own beams there (art. 657).

Recesses or structures resting on the wall. Neither neighbour may make a recess in the wall, or attach or rest a structure against it, without the other’s consent. Failing that, they must have experts determine the measures needed so that the structure does not harm the neighbour’s rights (art. 662).

Windows. No window or opening, “even with fixed glazing”, may be made in a party wall without the neighbour’s consent (art. 675).

Raising the wall (exhaussement). Each co-owner may have the wall raised. They then pay alone (art. 658):

• the cost of raising it;
• maintenance above the height of the shared boundary wall;
• the costs of maintaining the shared part arising from the raising;
• the expenses the raising makes necessary for the neighbour.

If the wall cannot bear the extra height, they must have it entirely rebuilt at their own expense, with any extra thickness taken on their side (art. 659). The raised section belongs to them. The neighbour can acquire a share in it by paying half the cost, estimated at the date of acquisition, and half the land provided for the extra thickness (art. 660). According to service-public.gouv.fr, raising the wall is impossible if structures belonging to the neighbour rest on the top (faîte) of the wall (F2415).

In the event of disagreement

Before going to the tribunal judiciaire (civil court) for the place where the property is located, service-public.gouv.fr recommends a conciliateur de justice (court conciliator, free of charge), a mediator (paid) or a procédure participative (collaborative procedure) with a lawyer (F2415). This attempt becomes compulsory, on pain of the claim being inadmissible, when the claim is for a sum not exceeding €5,000 or concerns an abnormal neighbour nuisance (trouble anormal de voisinage) (code de procédure civile (Code of Civil Procedure), art. 750-1). See also our guide on bornage et troubles de voisinage (boundary-fixing and neighbour nuisance).

Which professional to consult

The géomètre-expert (chartered land surveyor) locates the boundary line and indicates whether the wall stands on it, which is the condition for buying a share in it according to service-public.gouv.fr. The notaire (notary) draws up the deed acquiring a share in the wall, can record a surrender of the wall or the recognition of thirty years’ possession, and searches the title deeds for any agreement concerning the wall (F2415).