Quotient familial: how children reduce French income tax

French income tax is calculated on the basis of household shares (parts de quotient familial): a married or PACS couple has two, and a single person has one. Under the rules, the first two dependent children add half a share each, and the third and every child after that add a full share. The saving from each extra half-share is limited to €1,807 (plafonnement du quotient familial).

How many shares children add

Dependent children	Married or PACS couple	Single parent (parent isolé) whose children live with them	Source
0	2	—	service-public F2705
1	2.5	2	service-public F2705, F35120
2	3	2.5	service-public F2705, F35120
3	4	3.5	service-public F2705, F35120
Each additional child	+1	+1	service-public F2705, F35120

Who counts as a dependent child (enfant à charge)

Service-public lists three cases, and any one of them is enough:

• the child is a minor (mineur);
• the child has a disability, whatever their age, that prevents them from supporting themselves;
• the child is an adult who has been attached to the tax household (rattaché au foyer fiscal).

For couples and for single parents alike, the pages refer to children who are "minors, or adults who are not married" (mineur ou majeur célibataire).

How the system works

Household income is divided by the number of shares to give the quotient familial. Tax is calculated on that figure using the tax bands and then multiplied by the number of shares. More shares mean less income per share, and so a lower tax bill overall.

Service-public gives two worked examples for a couple with one child (2.5 shares):

Couple's net taxable income	Tax without the child	Tax with the child, before the limit	Saving from the child	Tax payable	Source
€63,000	€5,108	€3,740	€1,368, which is under €1,807, so the limit does not apply	€3,740	service-public F2705
€80,000	€10,208	€6,760	€3,448, which is €1,641 over €1,807	€8,401	service-public F2705

The limit on the saving (plafonnement du quotient familial)

For a couple, the saving from each extra half-share is limited to €1,807. The tax office runs two calculations: tax based on the actual number of shares, and tax based on 2 shares minus the limit for each extra share. If the first figure is lower than the second, the limit applies and the tax payable is the second figure.

Children who live with each parent in turn (résidence alternée)

When a child lives alternately with both parents, the saving is split between them. For a married or PACS couple:

Children in résidence alternée	Extra shares	Source
1	0.25	service-public F2705
2	0.5	service-public F2705
3	1	service-public F2705
Each additional child	+0.5	service-public F2705

The saving from each extra quarter-share is limited to €904.

Single parents (parent isolé)

A single person has 1 share, and a parent isolé gets an extra increase on top. For tax purposes, a parent isolé is someone who, on 1 January 2025, lived alone with their dependent children (or alone with a person with a disability whom they had taken into their home) and was single, divorced or separated. "Alone" means not living with a partner (concubinage); living with, for example, a child or grandchild (descendant) or a parent or grandparent (ascendant) does not count against it.

• Children who live only with that parent (garde exclusive). The first child adds a full share, half of which is for being a parent isolé. The saving from that full share is limited to €4,262.
• Children who live with each parent in turn (résidence alternée). The parent isolé increase is a quarter-share with one child and a half-share with two or more. That gives 1.5 shares in total with one child, 2 with two, and +0.5 for each additional child. The saving is limited to €2,131 per half-share for each of the first two children.

The parent isolé increase depends on box T (case T) being ticked on the return. Service-public advises checking whether it has already been ticked and ticking it if not.

What can change the answer

• A child holding a CMI card marked "invalidité". For a single parent, such a child adds a further half-share with garde exclusive, or a quarter-share with résidence alternée.
• A person with a disability living in the home. A couple gets a full share for each such dependant who holds a CMI card marked "invalidité", whatever their relationship, age or income.
• A single person who brought up a child alone for at least 5 years. If the three conditions set out on F2702 are met, the rules allow an extra half-share, with the saving limited to €1,079.

Who can confirm this

Service-public points to the tax information line (Service d'information des impôts) on 0809 401 401, Monday to Friday from 8:30 to 19:00, except public holidays. For questions about an individual tax file, the contact is the local tax office (service des impôts).

About Fiscly

Working out how many shares come from children, from résidence alternée or from single-parent status is easy to get wrong after a move. We went through this ourselves and built Fiscly for ourselves and for others who have moved here.

A questionnaire in six languages that ends with a step-by-step guide to the declaration.

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This material is for general information and does not replace individual advice.