From a national market
to a local club.
The first location needs a large enough audience within everyday reach. We screened metropolitan France at four geographic scales to identify where to investigate, then what each location still needs to prove.
1.5 km circles under the base income scenario.
Candidate catchments. Commercial viability remains to be established.
Explore from macro to local.
14 connected density concentrations show where audiences cluster at a broad scale. These exploratory shapes are not official agglomeration boundaries or a filter on the rest of the country.
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14 selected areas · Metropolitan FranceBlue: candidate areas · Orange: selected
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Urban concentrations
14 matching areas · Up to 3 can be compared
Source: fiscal data 2021. Income scenario: €30,000/UC, dispersion 0.35. Ordering is a demographic comparison, not a site or investment recommendation.
| Area | Adults 18+ | Ages 25–54 | Ages 25–64 | Income estimate 25–64 | Target / estimate | Compare |
|---|---|---|---|---|---|---|
| 3,878,694 | 2,137,599 | 2,706,627 | 1,415,803 | 0.1% | ||
| 427,428 | 242,823 | 295,390 | 105,908 | 0.7% | ||
| 216,138 | 107,591 | 139,962 | 40,625 | 1.8% | ||
| 151,584 | 84,374 | 102,761 | 39,992 | 1.8% | ||
| 153,687 | 87,120 | 105,321 | 36,874 | 1.9% | ||
| 107,980 | 61,789 | 74,280 | 29,015 | 2.5% | ||
| 108,988 | 60,866 | 76,445 | 25,342 | 2.8% | ||
| 155,382 | 71,754 | 95,319 | 22,325 | 3.2% | ||
| 72,075 | 42,820 | 50,835 | 18,094 | 3.9% | ||
| 60,688 | 31,290 | 39,330 | 16,982 | 4.2% | ||
| 65,417 | 37,144 | 44,568 | 16,510 | 4.3% | ||
| 66,731 | 37,128 | 45,424 | 14,571 | 4.9% |
Each geographic layer is selected separately. Changing scale changes the candidate set; it does not shrink circles around fixed centres. Areas across scales overlap and their populations cannot be added.
A catchment is the unit of the business.
City size alone cannot tell us where a club will work. Density, the age mix and purchasing power need to meet within a journey a member can repeat several times a week.
The base screen finds substantial local concentrations outside Paris. Its first provincial circles are around Lyon, Villeurbanne, Marseille, Nantes, Toulouse and Bordeaux. They form a starting list for local investigation.
Île-de-France stays in the comparison so the scale is visible. A larger population is useful context. It does not supply a conversion rate for a different club, offer or city.
Locate the population.
Fiscal population and source age bands describe who lives in the selected cells. Income scenarios indicate how the comparison changes with assumed purchasing power.
Establish who we can serve.
A real address, travel times, the offer and competing alternatives define the reachable market. This layer needs local evidence.
Demonstrate who will pay.
Price acceptance, acquisition, attendance and retention turn potential into a business. The model’s membership target is a requirement to test.
The current screen sizes geographic populations. It does not yet establish a validated addressable revenue market or a rollout capacity.
From a bassin to a neighbourhood.
Marseille Sud is the first detailed case study. The same local work can be extended to any candidate identified above.
We evaluated 705 centres inside the 6th–8th arrondissements, then selected 12 alternatives for comparison. Their catchments overlap. These are search areas, not available properties or independent markets.
Income controls apply only to this local study. National results above retain their stated base scenario. These nine scenarios are not confidence bounds.
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Grey boundaries: 75 IRIS statistical areas; the centre’s IRIS has a solid outline. IGN/INSEE · 2026 · Licence Ouverte 2.0.
Overlapping alternatives · 6th–8th arrondissement centresBlue: candidate areas · Orange: selected
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Martinique
Vauban · IRIS 132060604
- Census residents · 2022
- 2,237
- Census ages 25–54 · 2022
- 940
- Median income · 2021
- €26,240/UC
IRIS is INSEE’s local statistical unit. These figures describe the centre’s IRIS, a different boundary from the circle. Census and fiscal populations differ; they are not added. Annual income medians are published for 66 of the 75 areas, with nine unavailable. Boundaries are from 2026; historical boundary equivalence is unverified.
Download all 75 neighbourhoods and their boundaries ↓Compare all 12 local alternatives in this scenario
| Centre | Ages 25–54 full circle | Income estimate full circle | Income estimate inside 6th–8th | Target / inside estimate |
|---|---|---|---|---|
| 38,878 | 16,596 | 15,526 | 4.6% | |
| 53,944 | 15,106 | 9,099 | 7.8% | |
| 47,371 | 13,924 | 11,017 | 6.5% | |
| 39,755 | 13,378 | 10,998 | 6.5% | |
| 24,568 | 12,059 | 11,700 | 6.1% | |
| 22,403 | 11,508 | 11,309 | 6.3% | |
| 26,274 | 10,066 | 7,933 | 9.0% | |
| 14,465 | 9,287 | 9,280 | 7.7% | |
| 26,636 | 9,108 | 7,917 | 9.0% | |
| 16,548 | 8,052 | 6,408 | 11.1% | |
| 15,233 | 7,504 | 3,928 | 18.1% | |
| 12,259 | 6,002 | 5,969 | 11.9% |
Vauban is first or second among these fixed centres across the nine 1.5 km income scenarios. Périer and Bompard keep most of their population inside the study perimeter. Access and property evidence must decide between actual addresses.
Four tests before a location decision.
| Investment question | Evidence to collect | Decision metric |
|---|---|---|
| Can members reach it regularly? | Walking, cycling, transit and driving times from real addresses at relevant hours. | Adults within 10, 15 and 20 minutes; dependence on people beyond the intended area. |
| Will the offer win paying members? | One concrete offer and price, local interviews, then a measurable reservation or deposit test. | Price acceptance, lead-to-deposit conversion and acquisition cost by catchment. |
| Is there a reason to choose this club? | Comparable local offers, total prices, hours, facilities and observed capacity constraints. | Reasons to switch or add a membership; expected use and later cohort retention. |
| Can the property support the economics? | Available floorplates, access, rent, fit-out and operating quotes entered into the financial model. | Members required, usable capacity and cash needs for that property. |
A transparent basis for comparison.
The screen uses the INSEE Filosofi 2021 metropolitan grid, released in February 2026. The calculation covers 2,298,582 populated cells and 62,592,659 fiscal individuals. Reference-year income is expressed in annual euros per consumption unit (UC), an adjustment for household size.
How areas are selected
The national screen evaluates circles on a 200 m grid. At each radius, it selects the largest base income estimates first and excludes centres within twice that radius. Selected circles within a national layer share no source-cell centres.
The minimum modelled population aged 25–64 is 4,000 at 1.5 km and 12,000 at 3 km and 5 km. These are screening settings, not viability thresholds. The layers are selected separately; a small bassin does not have to sit inside a selected larger area. Their totals cannot be added.
Urban concentrations are connected density shapes from the same base scenario. They are not official agglomeration boundaries. Their density, connection and minimum-size settings are documented in the downloadable method.
What the income estimate does and does not measure
The base model uses a €30,000/UC threshold and an assumed lognormal dispersion of 0.35. It fits each cell’s capped mean living standard, then applies the implied above-threshold share to its age counts. INSEE does not publish the joint local age-and-income distribution used by this assumption.
These are income scenarios, not observed affluent customers. The cell mean is capped at departmental P5/P95, and is not a median or salary. Some age and income values are imputed; their population exposure is shown for each candidate. Income has not been projected from 2021 to today’s prices.
The fiscal population differs from the census. It excludes institutional residents and homeless people; some students appear at their parents’ fiscal address. Nonresident daytime workers are not added. Income coverage does not establish interest, willingness to pay or retention.
Paris benchmarks and local-study limits
The reported 1,500 members at La Montgolfière Canal date from December 2019. Lamarck’s membership remains unreported in the sources checked. Member origins are unavailable. Neither figure establishes a local capture rate, so no Paris multiplier or automatic format verdict is applied.
Marseille combines a separate RP2022 census and Filosofi 2021 IRIS package with the grid study. Their populations and geographies differ. IRIS medians are not pooled, and census and fiscal counts are not added. The reused boundary geometry retains the source package’s vintage limitations.
Calculations were checked with ten focused tests and an independent raw-source comparison. These checks verify arithmetic and geography, not the income or commercial assumptions.