Is this analysis based on a real listing?

No. The ad shown here is fictional — it exists to walk through a complete dossier end to end. The price ranges and orders of magnitude do match the Nantes market as recorded DVF sales document it. On your own listing, every figure is recomputed from its address, its floor area and the sales around it.

Do I need an account to analyse a listing?

No. You can paste a listing and get a first dossier without signing up. The account is what lets you keep the dossier, add the diagnostics and the co-ownership minutes to it, and carry on the conversation with the agent.

Where does the reference price per m² come from?

From the DVF database: sales actually recorded by notaries and published by the French tax administration. We filter on the same property type, a comparable floor area and a tight radius around the address, then take the median — not the mean, which a single atypical sale would distort.

Does the AI make the numbers up?

No. The price gap, the median and the range are computed from DVF sales: arithmetic on public data. The AI comes in afterwards, to read the result, rank it and explain it. When a figure is missing, the dossier says so instead of filling the hole.

Which listings can I analyse?

Paste the URL of a Leboncoin ad, or the text of any listing — SeLoger, Jinka, an agency window card, a private seller's PDF. What matters is that the price, the floor area and the location are there.

How long does an analysis take?

A few minutes. The dossier queries several public registers before concluding; you don't have to stay on the page while it runs.

What changes when I upload the diagnostics and the co-ownership minutes?

A great deal. Those documents are where the decisive attention points live: works voted through, ongoing proceedings, the real service-charge figure, asbestos or lead, insulation. The dossier is re-read and updated with every document you add.

Example

Example of a property listing analysis

Here, in full, is what Aubaine produces from a listing: the asking price against sales actually recorded by notaries, what the ad leaves out, and what is left to check before you sign.

Worked example. The listing below is fictional — it was built to show a complete dossier. The orders of magnitude (local median, service charges, negotiation range) match the Nantes market as recorded DVF sales document it.

The listing under analysis

The dossier starts from what the ad declares: price, floor area, floor level, energy label, service charges. Those are carried over as-is — they are the starting point of the verification, never its conclusion.

68 m² two-bedroom flat with balcony — Nantes (44000), Hauts-Pavés / Saint-Félix

Property type: Flat, 3 rooms
Floor area (Carrez): 68 m²
Rooms: 3, including 2 bedrooms
Floor: 2nd of 4, no lift
Year built: 1968
Outdoor space: 4 m² balcony
Asking price: €289,000 (agency fees included)
Price per m²: €4,250/m²
Advertised energy label: E — 269 kWh/m²/yr · GHG D
Heating: Individual gas
Co-ownership: 24 lots — €1,320/yr in charges
Declared property tax: €1,180/yr

The verdict, in three sentences

A well-placed three-room flat in a liquid area, but advertised 10.4% above what the local market actually paid for comparable properties — with nothing in the floor level, the aspect or the condition to justify the gap. The main reservation is not the price, though: it is the energy label, advertised as an E when the certificate filed on the ADEME register for this address is an F.

The expert's view

At €289,000 this flat is priced like a renovated home in a building that isn't. The seller's asset is the liquidity of the area: they know a buyer will turn up. Their weakness is that an informed buyer will open on the energy-label discrepancy, which takes a minute to verify. An offer at €262,000, documented by the five comparable sales and by the filed certificate, is defensible and leaves room to sign around €270,000. Above €275,000 you are paying up front for works you will carry out yourself.

Is the price justified?

The gap to the market is not an opinion: it is a subtraction between the asking price per square metre and the median of sales actually recorded around the address, at comparable property type and floor area. Here is the calculation, and the sales it rests on.

Advertised price per m²

€4,250

€289,000 for 68 m² Carrez, agency fees included.

Local median

€3,850

Flats of 60 to 80 m² sold within a 500 m radius over 2023-2024 (DVF).

Gap to the market

+10.4%

That is €27,200 above what the area actually paid, at comparable floor area.

The sales used as reference

Five notarised sales in the area, filtered on the same property type and a close floor area. These are prices paid, not prices asked: no competing listing enters this calculation.

Location	Sale date	Floor area	Price paid	Price per m²
Rue Paul Bellamy	March 2024	71 m²	€272,000	€3,831
Rue Jean Jaurès	June 2024	66 m²	€258,000	€3,909
Rue de Bel Air	February 2024	62 m²	€240,000	€3,871
Rue Lamoricière	September 2023	73 m²	€281,000	€3,849
Boulevard des Belges	November 2023	64 m²	€243,000	€3,797

What argues for it, what argues against

Strengths

A liquid area: five comparable sales in eighteen months. Reselling will not depend on finding one particular buyer.
Carrez floor area consistent with the layout: 68 m² for three rooms, no room sacrificed to advertise a bedroom count.
Individual gas heating: the bill stays under control and does not depend on the co-ownership's decisions.
A 4 m² balcony: on this segment it is the feature that decides a resale — two of the five comparables had none.
A 24-lot co-ownership: small enough for decisions to pass, large enough to share the charges.

Weaknesses

Advertised 10.4% above the local median, with no feature that accounts for the gap.
An E advertised, an F on the register: in law, the home is a thermal sieve.
Charges of €19.4/m²/yr, above the usual band for comparable co-ownerships (€12 to €15/m²/yr).
A 1968 building with no external insulation: a façade renovation with insulation is likely within ten years.
Second floor without a lift: a deal-breaker for part of the buyer pool when you come to resell.

What the listing does not say

Each point below comes from a public register set against what the ad claims, or from a feature of the property whose consequences the ad does not draw. They are ranked by severity.

The filed energy certificate does not match the one in the ad
Critical
The ad shows an E at 269 kWh/m²/yr. The certificate registered with ADEME for this address is an F at 312 kWh/m²/yr. The gap changes what the property is: an F-rated home has been barred from the rental market since 2025, and its rent was already frozen before that. Ask for the certificate number, check its date — and make it the first item of your negotiation.
A façade renovation with insulation is likely in the medium term
Caution
A 1968 building, original façade, no external insulation visible in the photos. On a 24-lot co-ownership, that kind of programme commonly runs between €8,000 and €15,000 per lot. Ask for the last three sets of general-meeting minutes: a vote already passed binds you, a mere feasibility study announces what is coming.
Service charges above comparable buildings
Caution
€1,320 a year for 68 m², or €19.4/m²/yr, where a comparable co-ownership with no lift and no caretaker sits closer to €12-15/m²/yr. Ask for the breakdown by line over the last three financial years: the gap comes either from the managing agent's contract or from arrears absorbed by the other owners.
Moderate clay shrink-swell hazard on the plot
Worth noting
Recorded by Géorisques. On a collective building of this era it is something to check rather than a defect: look for cracks on the façade and in the stairwell, and ask whether a natural-disaster order has already covered the municipality.
Second floor, no lift
Worth noting
The ad does not present it as a constraint, but it filters buyers on resale. Of the five comparables, the two without a lift sold at the bottom of the range.

Questions to ask at the viewing

Each of these questions follows from a point in the dossier. They are phrased to obtain a document or a figure, not an impression.

1Can you send me the minutes of the last three general meetings?
2Has a façade renovation or external insulation been voted, studied, or even raised at a meeting?
3What were the running charges, excluding works, over the last three financial years?
4What is the reference number of the energy certificate filed for this home, and what is its date?
5Is there a statutory works fund, and what is this lot's balance in it?
6How long has the property been on the market, and has the price already been reduced?
7What is this lot's share of the general charges, in thousandths?
8Is any proceeding under way in the co-ownership: arrears, litigation, a dispute with the managing agent?

What to negotiate on

An offer is defended with documents, not with a percentage. Here are the four levers this dossier puts in your hands, from the most solid to the most circumstantial.

The gap to the market: €27,200

Five comparable notarised sales, same area, same size bracket, all between €3,797 and €3,909/m². The asking price sits outside that band with nothing about the property to explain it. It is the hardest argument to contest: it rests on prices paid, published by the tax administration.

The real energy label

An F on the register instead of the advertised E. Beyond the negotiating lever, it is something the seller will have to put right before the sale anyway. Price up what moving from F to D costs, and put that figure on the table.

The renovation to come

Until the general-meeting minutes prove otherwise, the provision falls to you after the sale. A programme voted before the preliminary contract remains the seller's: the date of the vote decides, not the date of the works.

How long the listing has been up

A property listed for more than three months in an area that sells in six weeks has already been turned down by the market. Ask for the date it first went on sale and the history of reductions: a seller who has cut once will cut twice.

Where these figures come from

No figure in this dossier is produced by the AI. Each one comes from a public register, dated and citable — or is presented explicitly as an assumption.

DVF — recorded property transfers: Sales actually recorded by notaries, published by the French tax administration on data.gouv.fr. It is the only database that says what was paid rather than what was asked. The dossier's median, range and comparables all come from it.
ADEME — the energy-certificate register: The energy certificate actually filed for the address. It lets you verify the advertised label rather than take it on trust.
Géorisques: Flooding, clay shrink-swell, radon, seismicity, soil pollution and natural-disaster orders recorded for the plot.
The listing itself: Price, floor area, floor level, charges and property tax as declared by the seller. Carried into the dossier as-is, never used as a market reference.

Read the full methodology

Frequently asked questions

Your listing, the same dossier

Paste the URL or the text of the listing you are looking at. The dossier is computed on its real address and floor area, not on a national average.

Analyse my listing See the methodology