Households without a car: 2.4%, a lower share than 99% of compared French towns
One-person households: 24% here and 35% in the typical compared French town. The 2023 Census put Sermaise’s population at 1,617, in 670 households. Flats account for 7.3%. Higher than in 77% of compared French towns: 9.7% of homes stand empty.
Throughout this page, the Essonne 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.
From 2012 to 2023, 79% of compared French towns grew faster than Sermaise: −2%
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 same years the median compared French town changed +5%, the median Essonne town +6%.
7.9% of residents are 15 to 24, fewer than in 93% of compared French towns
Shares of residents by age at the 2023 census.
Age groups · share of residents
Median age of the 3,798 compared French towns
■ Sermaise 46. The median compared French town: 44.
With a median age of 46, Sermaise is older than 63% of compared French towns. The wider picture: 11% of residents are 15 to 24 in the typical compared French town. Residents aged 65 and over: a fifth of the total.
Women and men · all residents
51% women, 49% men
About an even split. Median share of women: Essonne 51.3%, France 51.8%.
Sermaise: 33% of households are couples with children, above 88% 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 Essonne median and the France median
Living alone · share
By its share of single-parent households (5.9%), Sermaise is below 96% of compared French towns. Couples with children: 25% in the typical compared French town, for comparison. Each household has 2.4 people on average.
92% of homes are houses
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
Of all households, 6.3% moved in during the last two years and 24% have stayed three decades or more. Households in social housing are rarer here than in 99% of compared French towns. Second homes make up 2.3%, close to the figure in the typical compared French town.
Per consumption unit, the median standard of living is €32,330 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.
The median standard of living in Sermaise is €32,330 a year per consumption unit: higher than in 92% of compared French towns.
Sermaise sits above 90% of compared French towns for households headed by a manager or professional (21%)
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
Against a figure of 32% in the typical compared French town, the share of households headed by a retired person in Sermaise comes in at 35%. Just over one in ten households are headed by a manual worker, a lower share than in 69% of compared French towns. Across the comparison, 9.4% of households are headed by a manager or professional in the typical compared French town.
Each household is counted once, by the occupation of its reference person (usually the oldest working adult).
4.8% of residents are foreign nationals, more than in 55% 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 census found that 5.9% of residents are immigrants in Sermaise. The wider picture: 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.
Below 94% of compared French towns: 19% of residents 15 and over are single
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 Sermaise comes in at 48%. On average, 25% of residents 15 and over are single in the typical compared French town.
Graduates of higher education: 40%, a higher share than 78% of compared French towns
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
In the typical compared French town, the share of adults with no qualification is 19%; Sermaise has 14%. Across the comparison, 30% of adults out of school hold a higher-education qualification in the typical compared French town.
19th highest median age among 41 French towns of 1,617 to 2,582
The 40 compared French towns nearest in population, by median age. Hover for each one’s second homes and immigrants; click for its page.
At the ends of the range sit Villejust (37.2), the youngest, and Prayssac (62.3), the oldest.
Sermaise is older than every town around it
The nearest towns of 2,500 or more, colored by median age. Source: INSEE, census 2023.
| Town | Median age | 65+ | Second homes | Immigrants |
|---|---|---|---|---|
| Sermaise | 46 | 20% | 2.3% | 5.9% |
| Saint-Chéron 5,132 · 2 mi | 41.6 | 18% | 13% | 9.8% |
| Dourdan 11,415 · 3.6 mi | 40.6 | 18% | 2.2% | 15% |
| Breuillet 9,157 · 4.8 mi | 39.4 | 16% | 1.3% | 13% |
| Étréchy 6,986 · 5.2 mi | 43.8 | 23% | 1.6% | 8.5% |
| Boissy-sous-Saint-Yon 3,882 · 5.8 mi | 40.7 | 16% | 2% | 6% |
| Bruyères-le-Châtel 3,788 · 6.1 mi | 40.6 | 17% | 1% | 8.1% |
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 Sermaise
What is the population of Sermaise?
1,617 at INSEE’s 2023 census, 2% fewer than in 2012 (1,657).
How old are Sermaise’s residents?
The median age is 46, older than 63% of compared French towns. 22% are under 18 and 20% 65 or older.
How many second homes are there in Sermaise?
18, with occasional dwellings: 2.3% of all homes, against 2.1% for the median compared French town.
How many immigrants live in Sermaise?
INSEE counts 96 immigrants (born abroad, not French at birth), 5.9% of residents, and 78 foreign nationals (4.8%). The medians of compared French towns are 6.5% and 4.3%.
What is the median income in Sermaise?
€32,330 a year per consumption unit in 2023 (median of compared French towns €25,970). 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 4, 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.