The average price per m² in Osny is 3 616 €/m² for an apartment, based on actual notarised (DVF) sales. About 43 transactions are recorded each year.
Atmospheric illustration of Osny, a town of the Cergy-Pontoise conurbation, in the Val-d'Oise.
In Osny, an apartment changes hands on average for around 3 616 €/m², according to the sales registered by notaries and published in DVF data, the French notarised sales database. This figure rests on 52 apartment sales retained for 2025, and the municipality records around 43 a year: a real but limited flat market, driven by the residential blocks built since the 1970s in the new town neighbourhoods. The house remains the dominant form of housing, with 171 house sales in the database, between estate houses and the old houses of the old village. For an apartment, the year of construction, the energy label and the proximity of the station make the price vary more than the street itself.
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.
The Osny market benefits from its position on the edge of the Cergy-Pontoise conurbation: the municipality offers more houses and green spaces than the central neighbourhoods, while remaining connected to the neighbouring employment hubs. The business parks near the A15, including the Beaux-Soleils, and the public services of the neighbouring prefecture feed a steady demand from working households. The volume of apartment sales remains modest, which makes every listing visible and can slow negotiation on unusual properties. Family houses with gardens generally find buyers more easily than small units.
The energy performance certificate (DPE) weighs more and more in discussions, particularly for the detached houses and residential blocks built in the 1970s and 1980s. A property rated F or G suffers a discount, as the buyer factors the cost of insulation and heating into their offer. Conversely, a renovated house or a recent, well-rated apartment sells on the basis of the market price. If you are thinking of selling, an energy audit or quotes for works prepared in advance give you concrete arguments with buyers.
Osny sits above Cergy and Pontoise for apartment prices, and at a level very close to that of Vauréal. Its more residential and recent housing stock brings it closer to the outlying municipalities of the conurbation than to the two central hubs.
Osny appears in written records from the early 9th century, when part of its lordship was bequeathed to the abbeys of Saint-Denis, Saint-Martin de Pontoise and Chelles. The farming village of the Vexin français grew up around the église Saint-Pierre-aux-Liens, whose oldest parts date back to the 12th century and whose bell tower marks the transition from Romanesque to Gothic. The Le Sueur family dominated the lordship from 1500, before the maréchal de Chamilly became its lord in 1678. The château de Busagny, from the early 17th century, also recalls this seigneurial past.
The current château was begun in 1787 by Charles de Lameth, in a neoclassical style, to plans by the architect Jacques-Pierre Gisors. It owes its name of château de Grouchy to its last private owner, the marquis Jean de Grouchy, great-grandson of the Marshal of the Empire. The municipality bought the 42-hectare estate in 1987 and moved its municipal services there in 1989. Since 1999 the former stables have housed the departmental firefighters' museum of the Val-d'Oise, and the landscaped park retains its dovecote, its ice house and its temple of love.
The railway changed the scale of the village: the Paris to Dieppe line was built around 1860 and the station opened in 1866, which markedly increased the population. Camille Pissarro, who settled in Osny in 1883 and 1884, painted many canvases there. The real turning point came from the 1970s onwards, with the integration of the municipality into the new town of Cergy-Pontoise. The neighbourhoods of the Ravinière, the Vauvarois and the Val de Viosne, as well as the business parks near the A15, date from this period of growth.
Osny has 17 954 inhabitants and keeps a markedly residential character: around six dwellings in ten are houses, according to data from INSEE, the French statistics institute, as reported by the online encyclopaedia. Owner-occupiers account for roughly two thirds of households, a higher proportion than in the central municipalities of the conurbation. Buyers are often families who work in Cergy, in Pontoise or in the Paris region and are looking for a garden without leaving the transport network. Apartments tend to attract first-time buyers, couples and single people aiming for a first purchase close to the station. The old village, around the church and the château, offers a rarer stock of older properties, negotiated case by case.
Our benchmark for an apartment in Osny stands at 3 616 €/m², calculated from DVF sales in 2025. It is an average over some fifty transactions, so an order of magnitude rather than a guaranteed price. A recent, well-insulated residential block may sit above it, a building from the 1970s with energy works to plan below it. For your property, the online valuation tool refines this benchmark according to floor area, floor level and condition.
Osny divides between the old village, around the église Saint-Pierre-aux-Liens and the parc de Grouchy, and the neighbourhoods built with the new town, such as the Ravinière, the Vauvarois or the Val de Viosne. The old village brings together old stone houses and a few character properties. The more recent neighbourhoods mix estate houses and small residential blocks. To the south, towards the A15, the Beaux-Soleils zone is above all a business area, not a residential one.
Osny station is served by Transilien line J, which runs to Paris Saint-Lazare. By road, the A15 motorway runs along the south of the municipality and the D915, the former route nationale 15, passes to the north. Several bus lines link Osny to Cergy and Pontoise, whose stations give access to the RER A and the RER C. This dual access, by train and motorway, weighs in the choice of many buyers who work outside the municipality.
Houses clearly dominate the local market, with 171 sales recorded in the database, against around 43 apartment sales a year. Houses sell on average for around 3 462 €/m², a level close to that of apartments, but the living area and the land push up the total budget. An apartment is better suited to a first purchase or a project without outdoor upkeep. For a house, the size of the plot, the year of construction and the energy performance explain most of the price differences.
The église Saint-Pierre-aux-Liens, the château de Grouchy and the colonne de Réal are protected as historic monuments. In their surroundings, works visible from the street, such as a roof, windows or a fence, require the opinion of the Architectes des Bâtiments de France, the state heritage architects. The Viosne runs through the municipality: for a property near the river, consult the risk disclosure statement (état des risques) attached to the preliminary sale agreement and the Géorisques map. Finally, the local urban plan (PLU), available at the town hall, sets out the possibilities for extending a building on your land.
This analysis is published by Immover, an independent observatory founded by Antony Barbier. Data sourced from official sources (DVF, INSEE, Notaries of France).