My neighbour is building a block of flats: will my house lose value?

A notice has gone up on the neighbouring plot: a four-storey block, twenty-four flats, balconies facing your garden. You bought this house in France for its sunny terrace and the view over the fields. You wonder what it will be worth once the works are finished, whether you can oppose the project, and whether anyone owes you anything. This guide explains the two routes open to you, their time limits, and how the loss of value is costed.

What happens in practice

The planning permission was granted by the town hall. Its display on the site, on a notice visible from the public road, starts the time limit for third-party challenges (article R. 424-15 of the French Planning Code). The planning file can be consulted at the town hall: site plan, sections, elevations, statement. That is the first thing to obtain, because everything starts from the plans.

Two timetables overlap.

The challenge to the permission goes to the administrative court. It must be brought within two months from the first day of a continuous two-month period of display (article R. 600-2). The challenge, whether an internal appeal or a court action, must be notified to the authority that issued the decision and to the holder of the permission within fifteen days, failing which it is inadmissible (article R. 600-1). The neighbour must show that the project is likely to affect directly the conditions of occupation, use or enjoyment of their property (article L. 600-1-2). The Conseil d’État (the French supreme administrative court) accepts that an immediate neighbour has in principle a sufficient interest where they point to features of the nature, size or location of the project (CE, 13 April 2016, no. 389798). This challenge seeks the annulment or amendment of the permission, not compensation. A challenge that goes beyond the defence of the claimant’s legitimate interests may give rise to damages in favour of the holder of the permission (article L. 600-7): the file must therefore be serious.

The action for compensation goes to the tribunal judiciaire, on the basis of trouble anormal de voisinage (abnormal neighbourhood disturbance, the French law of nuisance). It is time-barred after five years (article 2224 of the Civil Code) and can be brought after completion, when the disturbance is measurable. A court-ordered expert report can be requested before any trial (article 145 of the Code of Civil Procedure).

Between the two, negotiation is common. Many developers prefer an agreement signed before the works to a challenge that delays sales. The costing of the loss of value then serves as the basis.

What French law says

Abnormal neighbourhood disturbance. The owner, tenant or occupier who causes a disturbance exceeding the normal inconveniences of neighbourhood is strictly liable for the resulting damage (article 1253 of the Civil Code, created by Law no. 2024-346 of 15 April 2024). No fault is required, and compliance with planning rules is no defence. Liability is excluded where the disturbance comes from an activity that predates the arrival of the complaining neighbour and has continued in the same conditions.

Abnormality depends on the place. The Cour de cassation (the French supreme court for civil and commercial matters) holds that the loss of a view is not abnormal in an area that is being urbanised, where the disturbance is not precisely characterised (Cass. 3e civ., 9 November 2023, appeal no. 22-15.403, discussed on this site). It quashes an award for loss of view where the judges did not examine whether very high urban density excluded abnormality (Cass. 3e civ., 27 March 2025, appeal no. 23-21.076, discussed on this site). It does accept that a past disturbance is compensated even if it has ceased (Cass. 3e civ., 14 November 2024, appeal no. 23-20.880).

Views. The Civil Code sets the distances for opening direct views onto the neighbouring property, 1.90 metres, and oblique views, 0.60 metres (articles 678 and 679). A compliant building may nonetheless create an abnormal disturbance; a non-compliant building may be penalised as such.

Valuation. Market value is understood within the meaning of the Charte de l’expertise en évaluation immobilière (the French property valuation charter, 6th edition, November 2025, Title III, § 1.1), for a buyer informed of the surroundings and their foreseeable development. The report sets out its assumptions and reservations in writing (Title I, § 2.2).

What a valuation report changes

The method accepted by the courts is simple to state: value of the property without the disturbance, value of the property with the disturbance, the difference is the loss. Everything turns on the justification of the difference.

The report first establishes the value before, by comparison, at the relevant date. It then analyses the disturbance from the plans in the planning file: distances and heights, views created room by room and over the garden, loss of sunlight by a sun-path diagram at the solstices and equinoxes, loss of privacy, foreseeable noise. It places all this in context: zoning, density of the district, what a buyer could have anticipated. It looks for sales of comparable properties with and without an equivalent overlooking, and derives a reasoned deduction. From that it draws the value after and the loss of value in euros and as a percentage. It costs separately the temporary loss of enjoyment during the works, by reference to the rental value over the duration of the works.

This report serves three times: to establish a sufficient interest before the administrative court, to negotiate with the developer, and for the civil action, where it will be updated once the building is up.

What it does not do: it does not say whether the permission is lawful, which is a matter for a planning lawyer; it does not decide that the disturbance is abnormal, which is for the court; it does not stop the works.

A worked example

A house in Quimper, €380,000 before the project, with a south-facing terrace and a garden open onto a meadow. The neighbouring permission authorises a four-storey block, ground floor plus three, twenty-four flats, twelve metres from the terrace, with balconies facing the garden.

The report measures a loss of sunlight of two hours a day on the terrace and in the living room from November to February, direct views created from twelve balconies onto the garden and the kitchen, and the disappearance of the open view. The district is one of detached houses, zoned as urban land to be densified in the local plan, which lessens the abnormal character without removing it. On five sales of comparable houses, those directly overlooked by a block of flats sold for between 6 and 9 % less than the others. The report adopts 8 %, that is a loss of value of €30,400. The eighteen-month works cause a partial loss of enjoyment estimated at 15 % of a rental value of €1,300 a month, that is €3,510. Total loss costed: about €34,000.

In an already dense town-centre district, the same analysis might have concluded at a loss of value of 0 to 3 %, and the report would have said so. That is what makes it usable before a court, for the claimant as for the defendant.

Common mistakes

• Letting the two months pass. After that time limit the permission is final and only the civil action remains open.
• Forgetting to notify the challenge. Without notification within fifteen days to the applicant and the town hall, the challenge is inadmissible.
• Announcing 20 % without demonstration. An asserted percentage is regularly rejected; a percentage demonstrated by comparables is not.
• Confusing the lawfulness of the permission with the disturbance. A lawful permission may cause an abnormal disturbance; an unlawful permission does not necessarily create a loss of value.
• Waiting for the end of the works to do everything. The prospective costing from the plans serves the challenge and the negotiation; it is updated afterwards.
• Bringing a challenge without a file. Article L. 600-7 allows the developer to claim damages against a challenge that goes beyond the defence of legitimate interests.

What to gather

• A dated photograph of the site notice.
• The planning file consulted at the town hall: site plan, sections, elevations, statement.
• The title deed, the plans of the house, the property tax notice, surveys.
• Photographs taken from the living rooms and the garden, at different times of day and if possible in different seasons.
• The extract from the local planning plan for your plot and the project’s plot.
• Letters exchanged with the town hall or the developer, and any offer received.

Timeframe and fee

The service has two parts: the market value and rental value report on the house, about 15 hours, from €975, and the study of the loss, reading of the plans, overlooking, sunlight and reasoned costing of the loss of value, about 5 hours, from €325. Most often €1,300 in total travel not included, with the report usually delivered three to four weeks after the inspection and receipt of the planning file. Where the time limit for the challenge requires speed, a note based on the plans can precede the full report; the quote says so. Travel is charged at €65 per hour or part hour from PONT-L’ABBÉ, 50 % deposit on ordering, VAT not applicable, article 293 B of the French General Tax Code.

The Property loss of value page describes the report and the Fees page gives an example of a complete quote for a situation of this kind.