Half of Chilly-Mazarin is under 36.8, younger than 92% of compared French towns
Just over four in five homes are flats; in the typical compared French town the figure is 30%. Households headed by a retired person make up about one in five here (22%). On households in social housing, Chilly-Mazarin sits higher than 68% of compared French towns: 17%. This Essonne town had 20,443 residents in 8,720 households at the 2023 census.
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.
What stands out about the people of Chilly-Mazarin
Immigrants
INSEE counts 4,900 immigrants in Chilly-Mazarin (people born abroad who weren’t French at birth, whatever their nationality now): 24% of residents, against 13% for the median compared commune in Essonne. 20% are foreign nationals. Immigrants and foreign nationals ↓
A young town
Half of Chilly-Mazarin’s residents are under 36.8 and half over; the median of compared French towns is 44. 21% are under 15 and 14% are 65 or older. Ages ↓
Written from INSEE’s census 2023 on this page, against compared French towns.
A growing town: +6% since 2012, faster than 57% 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
Here the change came as +5% to 2017, then +1% to 2023.
14% of residents are 65 or over, fewer than in 94% 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
■ Chilly-Mazarin 36.8. The median compared French town: 44.
Little separates the share of residents aged 15 to 24 here, 11%, from the figure in the typical compared French town. To put it in context, 22% of residents are 65 or over in the typical compared French town.
Women and men · all residents
51% women, 49% men
About 95 men for every 100 women. Median share of women: Essonne 51.3%, France 51.8%.
A larger share of single-parent households than 86% of compared French towns: 13%
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
One-person households make up 38%, against 35% in the typical compared French town. In the typical compared French town, the share of single-parent households is 10%. Put another way, about one in four: 28% of households are couples with children.
A larger share of households without a car than 76% of compared French towns: 17%
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
Nothing unusual on second homes: 1.7%, close to the figure in the typical compared French town. About one in 18: that is how common empty homes are in Chilly-Mazarin (5.6%). In the typical compared French town, households without a car come to 11%.
€25,860 a year is the median standard of living here
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.
Half of residents live in households above €25,860 a year per consumption unit and half below; the level is lower than in 51% of compared French towns. As for poverty, 18.0% of residents are below the line.
In Chilly-Mazarin, 16% of households are headed by a manager or professional, more than in 78% 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
15% of households are headed by a manual worker. The comparison figure for households headed by a manager or professional is 9.4% in the typical compared French town.
Each household is counted once, by the occupation of its reference person (usually the oldest working adult).
Chilly-Mazarin sits above 96% of compared French towns for immigrants (24%)
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.
Against a figure of 4.3% in the typical compared French town, the share of foreign nationals in Chilly-Mazarin comes in at 20%. The comparison figure for immigrants is 6.5% 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.
Single residents make up 31% in Chilly-Mazarin, more than in 82% 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
In Chilly-Mazarin, 42% of residents 15 and over are married. Single residents: 25% in the typical compared French town, for comparison.
37% of adults out of school hold a higher-education qualification, more than in 71% 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
At 18%, the share of adults with no qualification is lower than in 57% of compared French towns. Graduates of higher education make up 30% in the typical compared French town.
Of 41 French towns its size (19,847 to 21,071 people), the 5th 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 Carrières-sous-Poissy (32.6), the oldest Concarneau (53.9).
Every neighbor is older than Chilly-Mazarin
The nearest towns of 2,500 or more, colored by median age. Source: INSEE, census 2023.
| Town | Median age | 65+ | Second homes | Immigrants |
|---|---|---|---|---|
| Chilly-Mazarin | 36.8 | 14% | 1.7% | 24% |
| Morangis 14,129 · 0.9 mi | 40.4 | 18% | 0.8% | 21% |
| Longjumeau 21,996 · 1.1 mi | 36.9 | 15% | 1.4% | 21% |
| Champlan 2,615 · 1.8 mi | 42.2 | 17% | 2.4% | 20% |
| Épinay-sur-Orge 10,722 · 1.9 mi | 40.7 | 18% | 1.7% | 15% |
| Savigny-sur-Orge 37,601 · 2 mi | 38.9 | 16% | 1.5% | 22% |
| Saulx-les-Chartreux 6,733 · 2.1 mi | 37.8 | 14% | 1.1% | 11% |
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 Chilly-Mazarin
What is the population of Chilly-Mazarin?
20,443 at INSEE’s 2023 census, 6% more than in 2012 (19,213).
How old are Chilly-Mazarin’s residents?
The median age is 36.8, younger than 92% of compared French towns. 25% are under 18 and 14% 65 or older.
How many second homes are there in Chilly-Mazarin?
160, with occasional dwellings: 1.7% of all homes, against 2.1% for the median compared French town.
How many immigrants live in Chilly-Mazarin?
INSEE counts 4,900 immigrants (born abroad, not French at birth), 24% of residents, and 4,090 foreign nationals (20%). The medians of compared French towns are 6.5% and 4.3%.
What is the median income in Chilly-Mazarin?
€25,860 a year per consumption unit in 2023 (median of compared French towns €25,970); 18.0% 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 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.