IMMO BTC — L3 study methodology, 21 September 2026

1. Scope
Ordinary apartment sales in Nice, 2016–2025. Main group: within a 500 m straight-line radius of the six new stops opened on 13 November 2019, from Méridia to Saint-Isidore (La Plaine, Les Arboras/Université, Eco-Parc, Stade). Coordinates average platforms sharing a name in the September 2026 Lignes d’Azur GTFS; current stop names are used. The previously opened shared section near the airport and Lingostière are excluded. Distance defines a reproducible boundary, not walking time.

2. Sources and selection
DGFiP / Etalab geo-DVF. For 2016–2020: archived copy of the official April 2021 release, hosted by OpenDataArchives. For 2021–2025: current files.data.gouv.fr release downloaded on 21 September 2026. Vintages may differ in late corrections. Ordinary Vente sales, one deed subdivision and municipality; exact row deduplication followed by exactly one Appartement row. Blank premises types and Dépendance are allowed; houses, commercial premises and transactions with multiple residential rows are excluded. Positive price and surface_reelle_bati; ratio EUR 500–25,000/m². Total consideration may include parking or other premises, without separate values. Etalab geocoding may represent the parcel rather than the building entrance.

3. Descriptive table
Median of individual total-price/floor-area ratios, rounded to the euro. Counts are selected sales with coordinates. The Nice median includes the nearby group. Nominal prices, without adjustment for inflation, condition, views or refurbishment. Article growth figures for 2018–2025 use the published rounded medians and are approximate.

4. Relative-trend model
Outcome: natural log of transaction price per m². Regressors: log floor area and its square, room-count categories, years, nearby-group membership, fixed effects for 500 × 500 m spatial cells and nearby-group/year interactions. Reference year: 2018. Grid origin: 7.1° E, 43.6° N. Approximate distances use 111,320 m per latitude degree and 111,320 × cos(43.7°) per longitude degree.
Apartments of 15–200 m² with 1–6 rooms. Cells must contain sales in 2016–2018 and 2020–2025. Main comparison group: more than 1,000 m from all six stops; the space between the nearby radius and 1,000 m is excluded. 2019 is estimated separately because opening took place in November.
The model adjusts observed characteristics and persistent spatial differences. Change = 100 × (exp(interaction coefficient) − 1), relative to the group difference in 2018. This is a relative growth measure, not a price-level gap or a percentage-point change.

5. Uncertainty and sensitivity
Errors are clustered by spatial cell. Approximate 95% intervals use 1.96 and finite cluster/parameter corrections. Main model: 71,083 observations and 177 clusters; the nearby group is much smaller. Intervals remain approximate, particularly with few nearby spatial areas.
Checks use 400 m and 600 m radii and a local comparison group 1–2 km away. 2025 estimates: −2.35% (500 m, city), +3.43% (500 m, local), −2.47% (400 m, city), −1.32% (600 m, city).
Trends already differed before opening: the main model’s relative 2016/2018 estimate is +10.67%. Parallel pre-trends are not supported. Anticipation, other development, changing housing composition and geocoding may matter. The model does not identify a separate causal tramway effect. A lack of a stable premium in these calculations does not prove that transport has no usefulness or no effect at a particular address.

6. Publication
Only aggregates, public stop coordinates and the radius diagram are published. No individual sales or addresses. Detailed results and source hashes follow.

Sources / Источники:
https://www.data.gouv.fr/datasets/demandes-de-valeurs-foncieres
https://files.data.gouv.fr/geo-dvf/latest/csv/
https://files.opendatarchives.fr/cadastre.data.gouv.fr/data/etalab-dvf/2021-04/csv/
https://transport.data.gouv.fr/resources/83178
DGFiP / Etalab — Licence Ouverte 2.0

{
  "created": "2026-09-21",
  "stations": [
    {
      "name": "Méridia",
      "lat": 43.682795,
      "lon": 7.2031515
    },
    {
      "name": "La Plaine",
      "lat": 43.687490499999996,
      "lon": 7.201601999999999
    },
    {
      "name": "Les Arboras/Université",
      "lat": 43.692721,
      "lon": 7.1992935
    },
    {
      "name": "Eco-Parc",
      "lat": 43.697773999999995,
      "lon": 7.1964955
    },
    {
      "name": "Stade",
      "lat": 43.7052025,
      "lon": 7.196584
    },
    {
      "name": "Saint-Isidore",
      "lat": 43.710432,
      "lon": 7.194595
    }
  ],
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        {
          "year": 2025,
          "relative_change_pct": -1.32,
          "ci95_low": -7.28,
          "ci95_high": 5.04,
          "log_coefficient": -0.013240419504087997,
          "cluster_se": 0.0318260684395726
        }
      ]
    }
  ],
  "hashes": [
    {
      "year": 2016,
      "sha256": "c9c4beb1f418f765dd9d4129b60ad8d810036fb4ea0c1d7bb1ffbc1ec6158c1f"
    },
    {
      "year": 2017,
      "sha256": "afa6f339da46459959989f7a078fcbf1c8ae011e024830f46966f04e5e21b497"
    },
    {
      "year": 2018,
      "sha256": "e21fcc1828dbb1b3847360fd141a4e5b086991a10b7d0fb53f14e42329d9e229"
    },
    {
      "year": 2019,
      "sha256": "fb916905a217a6c5cc4185eb096838e298d7689ca57c2014961c82d5a4f2a92c"
    },
    {
      "year": 2020,
      "sha256": "456b510e585056f80f8140e241e1eeb35dea9cf2ef4e46fe0df4e1801b15797d"
    },
    {
      "year": 2021,
      "sha256": "d39d9f68e3754929a08b75a8d0fc1a1690322044f837d19ef79e5e935be2260a"
    },
    {
      "year": 2022,
      "sha256": "81f87a3e69fb4c557b1abbc542ad26dadaa44ecc0084775659bb49594a3848ad"
    },
    {
      "year": 2023,
      "sha256": "5ba250e332ef0e06d4a4e9e12e978e808a005e1506d4df6697be41ace1d1a658"
    },
    {
      "year": 2024,
      "sha256": "531cff97a02ed5a80b6c0b5233ad5e0c394a7537b6854c91f0471fbc7a0d31f7"
    },
    {
      "year": 2025,
      "sha256": "4bd72468e8ca00ff99e5774730faf2cc9339c94a19b8c6db8cb95255370d07f0"
    }
  ],
  "method": "Ordinary single-apartment sales. Annual descriptive medians plus log EUR/m2 regression with log area, squared log area, room-count effects, year effects, 500m spatial cell effects and near-station/year interactions (2018 reference). Models restrict area 15–200 m2 and 1–6 rooms; cells must exist before and after opening. Control properties >1000m from the six new stops; local control <=2000m. Cluster-robust approximate 95% intervals by spatial cell. Observational association, not isolated causal effect."
}

Stop coordinates: Lignes d’Azur, Open Licence 2.0. Checked on 21.09.2026.
https://transport.data.gouv.fr/datasets/donnees-statiques-et-dynamiques-du-reseau-de-transport-lignes-dazur