Treffort ranks below 99% of compared French towns on households without a car: 2.9%
The share of one-person households is 24%, against 35% in the typical compared French town. Fewer flats than in 97% of compared French towns: 3.9%. Treffort’s 110 households held 249 residents at the 2023 Census. Across Treffort, 3.1% of homes stand empty.
Throughout this page, the Isère 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 Treffort
One home in seven is a second home
The census counted 19 second homes and occasional dwellings in Treffort, 15% of its 130 homes: higher than in 91% of compared French towns. 95% of them are houses. Their owners live elsewhere, so they aren’t in the population figures on this page. Homes & cars ↓
A town of families
34% of households are couples with children and 9.3% single parents with children; 19% of residents are under 15. Households ↓
Written from INSEE’s census 2023 on this page, against compared French towns.
15% of homes are second homes, a share 91% of compared French towns don’t reach
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
Some 9.3% of households are newcomers of under two years, against 12% who have been there 30 years or more. Second homes make up 2.1% in the typical compared French town. Households in social housing are rarer here than in 99% of compared French towns.
−3% since 2012, a pace below 81% 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
From 2012 to 2017 the change was +14%; from 2017 to 2023, −15%. Over the same years the median compared French town changed +5%, the median Isère town +7%.
Below 95% of compared French towns: 7.6% 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
■ Treffort 47.3. The median compared French town: 44.
With a median age of 47.3, Treffort is older than 71% of compared French towns. The usual figure: 11% of residents are 15 to 24 in the typical compared French town. The share of residents aged 65 and over stands at 18%.
Women and men · all residents
51% women, 49% men
About 96 men for every 100 women. Median share of women: Isère 51.3%, France 51.8%.
Couples with children: 34%, a higher share than 90% 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 Isère median and the France median
Living alone · share
There are 2.3 people in the average household. In the typical compared French town, couples with children come to 25%. Treffort has fewer single-parent households than 63% of compared French towns, at 9.3%.
The median resident lives on €32,870 a year per consumption unit
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 €32,870 a year per consumption unit: higher than in 93% of compared French towns.
More households headed by a manual worker than 97% of compared French towns: 26%
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
The share of households headed by a retired person is 28%, against 32% in the typical compared French town. On top of that, 4.6% of households are headed by a manager or professional, fewer than in 88% of compared French towns. The comparison figure for households headed by a manual worker is 14% in the typical compared French town.
Each household is counted once, by the occupation of its reference person (usually the oldest working adult).
Below 98% of compared French towns: 0.7% of residents are foreign nationals
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 trails nearly three quarters of compared French towns: 3.9%. Foreign nationals make up 4.3% 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.
Only 16% of residents 15 and over are single in Treffort
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
Half of residents 15 and over are married (typical compared French town: 43%). Single residents: 25% in the typical compared French town, for comparison.
11% of adults out of school have no qualification, fewer than in 90% 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
44% of Treffort’s residents 15 and over who have left education hold a higher-education diploma, against 30% in the median compared French town; 11% have no diploma (19%).
Of 41 French towns its size (249 to 2,582 people), the 15th oldest
The 40 compared French towns nearest in population, by median age. Hover for each one’s second homes and immigrants; click for its page.
Ages run from 37.2 in Villejust to 62.3 in Prayssac.
Around Treffort, 2 of 6 towns have a higher median age
The nearest towns of 2,500 or more, colored by median age. Source: INSEE, census 2023.
| Town | Median age | 65+ | Second homes | Immigrants |
|---|---|---|---|---|
| Treffort | 47.3 | 18% | 15% | 3.9% |
| La Mure 4,963 · 6.4 mi | 49.5 | 30% | 5.1% | 8.2% |
| Saint-Georges-de-Commiers 2,699 · 8.8 mi | 43 | 21% | 1.5% | 4% |
| Vif 8,530 · 9.4 mi | 44.2 | 20% | 1.5% | 5.1% |
| Champ-sur-Drac 3,335 · 11.8 mi | 44.9 | 23% | 1.2% | 6.1% |
| Villard-de-Lans 4,328 · 12 mi | 51 | 28% | 64% | 3.7% |
| Vizille 7,292 · 12.4 mi | 44 | 23% | 2.4% | 8% |
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 Treffort
What is the population of Treffort?
249 at INSEE’s 2023 census, 3% fewer than in 2012 (256).
How old are Treffort’s residents?
The median age is 47.3, older than 71% of compared French towns. 23% are under 18 and 18% 65 or older.
How many second homes are there in Treffort?
19, with occasional dwellings: 15% of all homes, against 2.1% for the median compared French town.
How many immigrants live in Treffort?
INSEE counts 10 immigrants (born abroad, not French at birth), 3.9% of residents, and 2 foreign nationals (0.7%). The medians of compared French towns are 6.5% and 4.3%.
What is the median income in Treffort?
€32,870 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.