A lower share of households in social housing than 97% of compared French towns, at 1.7%
Against a figure of 22% in the typical compared French town, the share of residents aged 65 and over in Trept comes in at 16%. At the 2023 Census Trept was home to 2,095 people in 890 households. Flats make up about one in ten here (10%). Households headed by a manager or professional are more common here than in 80% of compared French towns.
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 Trept
A town of families
34% of households are couples with children and 8.5% single parents with children; 20% of residents are under 15. Households ↓
Written from INSEE’s census 2023 on this page, against compared French towns.
Trept grew +14% from 2012 to 2023, ahead of 80% 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
The median Isère town changed +7% and the median compared French town +5%; here the first five years brought +18% and the next six −3%.
A median age of 41.2: Trept is younger than 72% 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
■ Trept 41.2. The median compared French town: 44.
The figure for residents aged 15 to 24 is 9.9% in Trept and 11% in the typical compared French town.
Women and men · all residents
50% women, 50% men
About an even split. Median share of women: Isère 51.3%, France 51.8%.
34% of households are couples with children, more than in 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
28% of households are one person living alone (typical compared French town: 35%). Lower than in nearly three quarters of compared French towns: 8.5% of households are single parents. Against that, 25% of households are couples with children in the typical compared French town. A household here holds 2.4 people on average.
Fewer households without a car than 95% of compared French towns: 3.9%
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
Where 2.1% of homes are second homes in the typical compared French town, Trept has 4.2%. The comparison figure for households without a car is 11% in the typical compared French town. 19% of households have been in place 30 years or more; 12% moved in within the last two years. At 7.8%, the share of empty homes is higher than in 62% of compared French towns.
Median living standard: €28,990 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.
At €28,990 a year per consumption unit, the median standard of living here is higher than in 78% of compared French towns.
Below 76% of compared French towns: 27% of households are headed by a retired person
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
In the typical compared French town, the share of households headed by a manual worker is 14%; Trept has 18%. Households headed by a retired person: 32% in the typical compared French town, for comparison.
Each household is counted once, by the occupation of its reference person (usually the oldest working adult).
A lower share of immigrants than 78% of compared French towns, at 3.5%
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 median compared commune in Isère has 8%; immigrants here make up a share lower than in 78% of compared French towns. The wider picture: 6.5% of residents are immigrants in the typical compared French town. For Trept, the census puts foreign nationals at 1.8%.
INSEE publishes no country of birth or ethnicity by commune in these tables, and the census doesn’t ask about religion.
21% of residents 15 and over are single, below 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
Compared with 43% in the typical compared French town, 46% of residents 15 and over are married here. The share of single residents in the typical compared French town is 25%.
In Trept, 14% of adults out of school have no qualification, fewer than in 76% 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
Against a figure of 30% in the typical compared French town, the share of graduates of higher education in Trept comes in at 33%. For comparison, 19% of adults out of school have no qualification in the typical compared French town.
Among 41 French towns of 2,095 to 2,582 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.
Ages run from 37.2 in Villejust to 62.3 in Prayssac.
Of the 6 towns nearest Trept, 5 are older
The nearest towns of 2,500 or more, colored by median age. Source: INSEE, census 2023.
| Town | Median age | 65+ | Second homes | Immigrants |
|---|---|---|---|---|
| Trept | 41.2 | 16% | 4.2% | 3.5% |
| Saint-Chef 3,921 · 4 mi | 43.3 | 19% | 2.1% | 4.1% |
| Crémieu 3,536 · 4.3 mi | 43.3 | 21% | 4.3% | 9.6% |
| Saint-Savin 4,323 · 4.4 mi | 43.8 | 18% | 1.3% | 3.7% |
| Saint-Romain-de-Jalionas 3,417 · 6.7 mi | 44.4 | 21% | 0.6% | 5.8% |
| Morestel 4,340 · 6.9 mi | 46.2 | 26% | 1.3% | 7.6% |
| Bourgoin-Jallieu 30,151 · 7 mi | 37.9 | 18% | 1.9% | 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 Trept
What is the population of Trept?
2,095 at INSEE’s 2023 census, 14% more than in 2012 (1,836).
How old are Trept’s residents?
The median age is 41.2, younger than 72% of compared French towns. 25% are under 18 and 16% 65 or older.
How many second homes are there in Trept?
42, with occasional dwellings: 4.2% of all homes, against 2.1% for the median compared French town.
How many immigrants live in Trept?
INSEE counts 73 immigrants (born abroad, not French at birth), 3.5% of residents, and 37 foreign nationals (1.8%). The medians of compared French towns are 6.5% and 4.3%.
What is the median income in Trept?
€28,990 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.