The average price per m² in L'Isle-Adam is 4 498 €/m² for an apartment, based on actual notarised (DVF) sales. About 96 transactions are recorded each year.
Mood illustration of a residential municipality in the Île-de-France.
The average price in L'Isle-Adam stands at 4 498 €/m², according to the DVF database, which records sales actually registered before notaries. In the north of the Val-d'Oise the municipality stands apart for a setting hemmed in on three sides by the state forest and to the west by the Oise, which structurally limits the buildable area. Unlike coastal or mountain municipalities, the market here is a genuine residential market: nine dwellings in ten are main residences.
Prices from the DVF file (Demandes de valeurs foncières, published by the DGFiP), transactions actually recorded at the notary at municipality level. Cross-referenced with the Notaires de France - INSEE indices. Learn more about our methodology.
After 4 257 €/m² in 2021, the average price in L'Isle-Adam reaches 4 498 €/m² in 2026, roughly +6 % over the period.
Unlike holiday municipalities, L'Isle-Adam has a market driven by residential demand. Second homes account for only 3,5 % of the stock, vacancy 6,5 %, and the population is rising steadily. Prices therefore respond above all to the appeal of the municipality for working Île-de-France households: quality of setting, the presence of the forest and the river beach, town-centre shops, access to Paris-Nord in under an hour.
The supply constraint is real but of a different nature from elsewhere. It comes not from coastal or mountain regulation but from geography: unbuildable state forest on three sides, river and islands to the west. On a territory of 14,9 km² already largely urbanised, output of new housing remains limited, which supports the level of values around 4 498 €/m² in 2026 despite continuous population growth.
Set back in its Île-de-France context, L'Isle-Adam sits well below the western inner-ring municipalities, while remaining above the average for the north of the Val-d'Oise.
The town owes its name to a man and to an island. In 1014, Adam I founded a priory on the island in the Oise where a first fort had been built around 865; the forms Insula in 1206 then Insula-Adam in 1223 fixed the place name. The castellany passed in 1364 to Pierre de Villiers, whose line would give the Villiers de L'Isle-Adam, then in 1527 to Anne de Montmorency, who had the church of Saint-Martin consecrated in 1567.
In the 17th century, the princes de Conti laid out the forest: an enclosing wall of twenty-five kilometres, a ha-ha to hold the game, and straight rides whose layout is attributed to Le Nôtre. In the 1780s, Pierre-Jacques Bergeret, who had travelled in Italy with Fragonard, had a Chinese pavilion built in his park at Cassan; it is now protected as a historic monument, was returned to the municipality in 1972, then restored and inaugurated in 1975.
The recent history is that of a holiday town turned residential town. In 1910, Henri Supplice turned the bathing spot on the Oise into a laid-out beach, a rare facility in the Île-de-France, renovated in 2015. The territory then organised itself into clearly identified sectors: the centre around the shopping Grande Rue, the islands of Le Prieuré and La Cohue, the park of Cassan and its some five hundred houses from a 1970s scheme, the former village of Nogent, the hamlet of Stors and the Grand Val retail hub.
L'Isle-Adam attracts Île-de-France households looking for a wooded setting without leaving the sphere of influence of Paris. The municipality gained 3,6 % inhabitants between 2017 and 2023, reaching 12 493 residents, and its stock is made up of 90 % main residences, with 56 % owners. The market mixes apartments in the centre, in the majority in the stock, and detached houses in the suburban districts. One point counts for the buyer: the station sits in Parmain, on the other bank of the Oise, which creates a real difference in accessibility between districts.
The average price in L'Isle-Adam is 4 498 €/m², calculated on the DVF transactions actually completed before notaries. That is a level clearly above the average for the north of the Val-d'Oise, without reaching that of the inner-ring municipalities.
About 48 minutes by direct train to Paris-Nord from the L'Isle-Adam - Parmain station, on line H of the Transilien. The station is however in the neighbouring municipality of Parmain, on the other side of the Oise: the time needed to reach it therefore varies appreciably depending on the district where the property sits.
Because the territory is framed by unbuildable spaces. The state forest of L'Isle-Adam, around 1 550 hectares, borders the municipality to the east and the south and accounts for 73 % of its rural space; the Oise and its islands close off the west. Out of 14,9 km² of municipal area, the surface genuinely available for new housing is therefore reduced.
No. The centre around the Grande Rue, the islands of Le Prieuré and La Cohue, the Cassan park estate, the suburban districts of La Faisanderie and La Garenne or the hamlet of Stors do not form a single market. The average price of 4 498 €/m² covers these gaps, which only a valuation taking the precise address into account can settle.
This analysis is published by Immover, an independent observatory founded by Antony Barbier. Data sourced from official sources (DVF, INSEE, Notaries of France).