Households in social housing make up 0.1% in Septeuil, less than in 99% of compared French towns
Couples with children: 32% here and 25% in the typical compared French town. More households headed by a manager or professional than in 90% of compared French towns: 21%. 2,264 residents in 880 households: that is Septeuil at the 2023 Census. Put another way, about one in seven: 14% of homes are flats.
Throughout this page, the Yvelines median and the France median are the median of compared communes (those with an overall grade), each figure its own median. Source: INSEE, census 2023.
A −2% change since 2012: slower than 77% of compared French towns
Residents at INSEE’s last three censuses, each recast in the 2026 commune boundaries. France has no yearly estimate by commune between censuses.
2012 to 2023
2017 to 2023
Over the whole period the median compared French town changed +5%, and the median Yvelines town +7%.
Above 80% of compared French towns: 12% of residents are 15 to 24
Shares of residents by age at the 2023 census.
Age groups · share of residents
Median age of the 3,798 compared French towns
■ Septeuil 44.8. The median compared French town: 44.
The median age in Septeuil is 44.8, higher than in 55% of compared French towns. Across the comparison, 11% of residents are 15 to 24 in the typical compared French town. Put another way, about one in five: just over a fifth of residents are 65 or over.
Women and men · all residents
51% women, 49% men
About an even split. Median share of women: Yvelines 51.6%, France 51.8%.
28% of households are one person living alone, below 84% of compared French towns
A household is everyone who shares a main home (résidence principale). Household types come from INSEE’s fuller sample of a quarter of census forms.
Against the Yvelines median and the France median
Living alone · share
Households here average 2.3 people each. As a yardstick, 35% of households are one person living alone in the typical compared French town. Little separates the share of single-parent households here, 9.6%, from the figure in the typical compared French town.
Above 80% of compared French towns: 5.9% of homes are second homes
Every home the census counted: main residences, second homes and occasional dwellings (INSEE counts them together), and empty homes. Owning and renting are on Cost of living.
All homes · share of homes
Type of home
Cars per household · share of households
Long tenure is the mark of 19% of households (30 years or more), short tenure of 13% (under two years). Lower than in 77% of compared French towns: 6.4% of households have no car. For comparison, 2.1% of homes are second homes in the typical compared French town. Empty homes: 8.4% here and 6.7% in the typical compared French town.
Median standard of living: €31,320 a year
The standard of living (niveau de vie) is a household’s disposable income after taxes and benefits, divided by its consumption units (UC) to allow for its size and make-up: 1 for the first adult, 0.5 for each other person 14 or older, 0.3 for each child under 14.
Medians of compared communes. Source: INSEE, Filosofi 2023.
Living standards centre on €31,320 a year per consumption unit: higher than in 89% of compared French towns. The poverty rate is 7.0%.
In Septeuil, 28% of households are headed by a retired person, fewer than in 76% of compared French towns
Households by the socio-professional group (PCS) of their reference person, INSEE’s own categories. Jobs and commuting are on the Work & commute page.
Households by reference person’s group · share of households
Just over one in ten households are headed by a manual worker, against 14% in the typical compared French town. The comparison figure for households headed by a retired person is 32% in the typical compared French town.
Each household is counted once, by the occupation of its reference person (usually the oldest working adult).
3.7% of residents are foreign nationals, fewer than in 56% of compared French towns
INSEE publishes two measures, which overlap but aren’t the same. Neither is the UK’s “born abroad”.
Share of residents · census 2023
Immigrant (immigré)
Born abroad, not French at birth. Someone stays an immigrant after becoming French. A French citizen born abroad (for example in Algeria before 1962) is not one.
Foreign national (étranger)
Not a French citizen today, wherever born. A child born in France to foreign parents can be a foreign national without being an immigrant.
The share of immigrants stands at 5.9%. That is lower than in 55% of compared French towns; the median compared commune in Yvelines has 15%. Typically, 4.3% of residents are foreign nationals in the typical compared French town.
INSEE publishes no country of birth or ethnicity by commune in these tables, and the census doesn’t ask about religion.
29% of residents 15 and over are single, more than in 73% of compared French towns
Residents 15 and over by how they live: the census asks both the legal status and whether people live as a couple.
Residents 15 and over · share
Against a figure of 43% in the typical compared French town, the share of married residents in Septeuil comes in at 41%. Across the comparison, 25% of residents 15 and over are single in the typical compared French town.
Above 74% of compared French towns: 38% of adults out of school hold a higher-education qualification
Highest diploma of residents 15 and over who have left education, in French terms: the levels don’t map one-to-one to UK or U.S. ones.
Highest diploma · 15 and over, out of education
On the census count, 18% of adults out of school have no qualification. For graduates of higher education, the comparison in the typical compared French town is 30%.
41 French towns of 2,264 to 2,582 people: this is the 18th youngest
The 40 compared French towns nearest in population, by median age. Hover for each one’s second homes and immigrants; click for its page.
The youngest is Villejust (37.2), the oldest Prayssac (62.3).
Every neighbor is younger than Septeuil
The nearest towns of 2,500 or more, colored by median age. Source: INSEE, census 2023.
| Town | Median age | 65+ | Second homes | Immigrants |
|---|---|---|---|---|
| Septeuil | 44.8 | 22% | 5.9% | 5.9% |
| Magnanville 6,383 · 5.5 mi | 43.1 | 22% | 0.5% | 16% |
| Garancières 2,621 · 6 mi | 42.6 | 18% | 6% | 6.1% |
| Mantes-la-Ville 22,332 · 6 mi | 35.2 | 14% | 0.7% | 24% |
| Buchelay 3,360 · 6.2 mi | 38.3 | 18% | 1.5% | 16% |
| Mézières-sur-Seine 3,923 · 6.9 mi | 38.8 | 14% | 1.4% | 11% |
| Porcheville 3,382 · 7 mi | 37.3 | 15% | 0.8% | 17% |
Health, work, housing and schools
What this data can and can’t tell you
- Census 2023. INSEE’s census is a rolling survey: a fifth of small communes each year, 8% of homes in large ones each year. “2023” pools the surveys of 2021 to 2025, so the figures describe the town around 2023, not on one day.
- Medians of compared communes. The comparisons are the median of the département’s compared communes and of France’s (those with an overall grade), each figure its own median: not the total for the département or for France, which large cities pull towards their own figures.
- Immigrants and foreign nationals. INSEE’s two measures: an immigrant was born abroad without French nationality; a foreign national isn’t French today. Neither is a count of people born abroad, which INSEE doesn’t publish by commune.
- Second homes. Homes used for holidays or weekends, with occasional dwellings (kept for work, for example), which INSEE counts together. Their owners are counted where they live, not here.
- Standard of living. INSEE’s Filosofi: disposable income per consumption unit, from tax and benefit files, 2023. The poverty rate is the share of residents below 60% of France’s median. Not published for the smallest communes.
- What France doesn’t ask. The French census asks nothing about ethnicity, religion, language or health, so this page has no such section.
Questions about who lives in Septeuil
What is the population of Septeuil?
2,264 at INSEE’s 2023 census, 2% fewer than in 2012 (2,302).
How old are Septeuil’s residents?
The median age is 44.8, older than 55% of compared French towns. 22% are under 18 and 22% 65 or older.
How many second homes are there in Septeuil?
61, with occasional dwellings: 5.9% of all homes, against 2.1% for the median compared French town.
How many immigrants live in Septeuil?
INSEE counts 130 immigrants (born abroad, not French at birth), 5.9% of residents, and 84 foreign nationals (3.7%). The medians of compared French towns are 6.5% and 4.3%.
What is the median income in Septeuil?
€31,320 a year per consumption unit in 2023 (median of compared French towns €25,970); 7.0% of residents live below the poverty line. Source: INSEE, Filosofi.
Sources: INSEE, census 2023 (population, ages, households, homes, marital status, diplomas, immigrants, foreign nationals, employment), 2026 geography · INSEE, Filosofi 2023 (standard of living, poverty) · IGN Admin Express (boundaries) · Medians and percentiles: TownRatings, over compared French towns, updated November 9, 2026. Under the Licence Ouverte / Open Licence 2.0 (Etalab).
Contains public sector information under the Licence Ouverte / Open Licence 2.0 (Etalab): INSEE, DGFiP, the Interior Ministry’s statistics service (SSMSI), the Ministry of Education (DEPP), the Health Ministry’s statistics service (DREES) and the Housing Ministry (Carte des loyers). Commune boundaries: IGN Admin Express.