Loss of value of the retained land (dépréciation du surplus)

When a compulsory purchase takes only part of a property, a strip of land to widen a road, a corner of a plot for a junction, the owner keeps the rest. But that remainder is not always worth, in proportion, what it was worth before: a house now 3 metres from the carriageway, a plot that has become too narrow to build on, a field cut in two, an access removed. This loss of value of the retained part is the dépréciation du surplus (loss of value of the retained land, close to what English practice calls severance or injurious affection). It is compensated in addition to the value of the land taken.

Where the retained land has become unusable in normal conditions, the owner may ask for the compulsory purchase to extend to the whole property: this is the réquisition d’emprise totale (request for total acquisition).

Where the rule comes from

The basis is article L. 321-1 of the French Expropriation Code, which requires the whole of the direct, material and certain loss caused by the compulsory purchase to be covered. The loss of value of the retained land is a direct loss caused by the taking, distinct from the dispossession itself, and the courts consistently compensate it as an ancillary head. The Expropriation Code also provides for the request for total acquisition for built plots and for land whose remainder can no longer be used normally.

The Charte de l’expertise en évaluation immobilière (French property valuation charter, Title III § 1.20) recalls that the principal compensation is accompanied by ancillary compensation covering every element of the loss suffered.

In a valuation report

I first value the whole property before the taking, then the land taken itself per unit of area on the basis of the classification of the entire plot, in line with the 2025 case law. I then value the retained land as it will stand after the works: area, shape, residual development potential in the light of set-back rules, access, nuisance from the new road. The loss of value is the difference between the value of the retained land before and after, excluding the value of the land taken so as not to count it twice. The report includes a before-and-after plan and, where relevant, the calculation of the development potential lost.

Example

A 1,200 m² plot in a developable zone, with a house on it, is worth €300,000 before the taking; bare land trades at €250 per m² in this sector. A road widening takes 150 m² at the front: the land taken is worth €37,500. The house ends up 4 metres from the road instead of 14, with greater exposure to noise and no front garden. By comparison with houses directly bordering the same road, I value the retained land at €235,000 instead of €262,500. Loss of value of the retained land: €27,500, to be added to the land taken and the reinvestment allowance.

Not to be confused with

The loss of value (moins-value) in property damage claims, the equivalent notion outside compulsory purchase, and the gain in value that the works may bring to the retained land, which the judge may take into account in certain cases provided by the Code.