French Income Tax: Calculation, Tax Brackets and Optimisation

Understanding the French Income Tax Mechanism

Income tax (impot sur le revenu, or IR) is the second-largest source of tax revenue for the French state, after VAT. It applies to approximately 18 million households out of the 40 million in France, meaning less than half of all households. Indeed, thanks to the progressive tax scale and various allowances, over half of French households pay no income tax at all.

However, for those subject to it, income tax can represent a considerable burden. A single person earning 50 000 euros of net taxable income pays approximately 7 400 euros of tax, i.e. an average rate of 14.8 %. A couple with two children earning 100 000 euros pays approximately 9 600 euros, i.e. 9.6 % average rate. Understanding the calculation mechanisms is the first step towards optimising your situation.

The 2026 Progressive Tax Scale

The income tax scale is progressive: income is divided into brackets, each taxed at an increasing rate. The scale applicable to 2025 income (2026 tax return) is as follows:

What the Progressive Scale Means

The progressive scale means that only the portion of income exceeding the threshold is taxed at the higher rate. A single person earning 35 000 euros does not pay 30 % on all their income. They pay:

• 0 % on the first 11 497 euros = 0 euros
• 11 % on the bracket from 11 497 to 29 315 euros (i.e. 17 818 euros) = 1 960 euros
• 30 % on the bracket from 29 315 to 35 000 euros (i.e. 5 685 euros) = 1 706 euros
• Total: 3 666 euros, i.e. an effective average rate of 10.5 %

The Marginal Tax Rate (TMI -- Tranche Marginale d'Imposition) is the rate applied to the last euro of income. In our example, the TMI is 30 %. This TMI determines the real benefit of any tax reduction scheme.

The Family Quotient: Sharing to Pay Less

The Family Quotient Principle

The family quotient (quotient familial) divides taxable income by a number of shares that depends on the composition of the tax household. This mechanism softens the progressivity of tax for families.

The number of shares is calculated as follows:

• Single, divorced or widowed: 1 share
• Married or civil partnership couple: 2 shares
• 1st and 2nd dependent child: +0.5 share each
• 3rd child and beyond: +1 share each
• Single parent: +0.5 additional share

Thus, a married couple with 3 children has 4 shares (2 + 0.5 + 0.5 + 1).

Family Quotient Capping

To prevent the family quotient from excessively benefiting high earners, a cap limits the tax benefit to 1 791 euros per half-share beyond the first (for a single person) or the first two (for a couple).

Practical example: a couple with 2 children (3 shares) and taxable income of 120 000 euros. Tax is calculated on 40 000 euros per share. The tax saving from the 2 children's half-shares is compared to the cap of 2 x 1 791 = 3 582 euros. If the calculated saving exceeds this cap, it is reduced to 3 582 euros.

The Spousal Quotient

Marriage or civil partnership (PACS) allows the couple's income to be pooled and divided by 2 shares. This advantage is greatest when the partners' incomes are very unequal. If one partner earns 80 000 euros and the other 20 000 euros, a joint return allows the brackets to be "smoothed" and progressivity to be reduced.

Conversely, if both partners earn similar amounts, marriage provides virtually no tax advantage in terms of income tax.

The Decote: A Mechanism for Modest Incomes

The decote is a mechanism that reduces the tax for households whose gross tax is below a certain threshold. It mainly benefits low-income taxpayers in the first tax bracket.

For 2025 income, the decote applies when gross tax is below:

• 1 929 euros for a single person
• 3 191 euros for a couple

The calculation formula is:

• Single: decote = 873 - (gross tax x 45.25 %)
• Couple: decote = 1 444 - (gross tax x 45.25 %)

If the result is negative, there is no decote. If positive, the tax is reduced accordingly.

The Exceptional Contribution on High Incomes (CEHR)

Taxpayers with the highest incomes are subject to an additional contribution, the CEHR, calculated on the reference fiscal income (revenu fiscal de reference):

This contribution is added to income tax and is not subject to the tax niche cap. It represents a significant surcharge for very high earners.

Step-by-Step Tax Calculation Simulation

Let's take the example of a married couple with 2 children, with the following income:

• Salary partner 1: 55 000 euros net taxable
• Salary partner 2: 35 000 euros net taxable
• Rental income: 8 000 euros net
• Total taxable income: 98 000 euros

Step 1: Determine the Number of Shares

Married couple: 2 shares + 2 children (0.5 + 0.5) = 3 shares

Step 2: Calculate the Quotient

Income per share: 98 000 / 3 = 32 667 euros

Step 3: Apply the Scale to One Share

• 0 % on 11 497 euros = 0 euros
• 11 % on (29 315 - 11 497) = 11 % on 17 818 = 1 960 euros
• 30 % on (32 667 - 29 315) = 30 % on 3 352 = 1 006 euros
• Tax for one share: 2 966 euros

Step 4: Multiply by the Number of Shares

Gross tax: 2 966 x 3 = 8 897 euros

Step 5: Check Family Quotient Capping

Let's calculate the tax for the couple alone (2 shares): 98 000 / 2 = 49 000 euros per share.

• 0 % on 11 497 = 0
• 11 % on 17 818 = 1 960
• 30 % on (49 000 - 29 315) = 30 % on 19 685 = 5 906 euros
• Tax for 2 shares: (1 960 + 5 906) x 2 = 15 731 euros

Benefit from the 2 children's half-shares: 15 731 - 8 897 = 6 834 euros Cap: 2 x 1 791 = 3 582 euros

The benefit exceeds the cap. The final tax is therefore: 15 731 - 3 582 = 12 149 euros

Step 6: Final Result

The couple pays 12 149 euros of income tax, i.e. an effective average rate of 12.4 %. The couple's TMI is 30 %.

Income Tax Optimisation Strategies

The Plan d'Epargne Retraite (PER)

The PER is the most powerful tax reduction tool because it allows you to deduct contributions from taxable income, outside the tax niche cap.

The deduction ceiling is the higher of:

• 10 % of the previous year's net professional income (ceiling of 35 194 euros in 2026)
• 4 399 euros (10 % of the PASS)

Unused ceilings can be carried forward for the following 3 years. It is also possible to use your spouse's ceiling.

For a household with a TMI of 41 %, a PER contribution of 15 000 euros generates a tax saving of 6 150 euros. This is equivalent to an investment with an immediate return of 41 %.

Charitable Donations

Donations qualify for an income tax reduction of:

• 66 % of the amount for donations to public interest organisations (cap of 20 % of taxable income)
• 75 % for donations to organisations helping people in difficulty (cap of 1 000 euros for the 75 % portion, beyond which the 66 % rate applies)

A donation of 1 000 euros to a food aid organisation generates a tax reduction of 750 euros, making the net cost only 250 euros.

Home Services Employment

Expenditure on home services (cleaning, childcare, tutoring, gardening) qualifies for a 50 % tax credit on amounts paid, up to 12 000 euros per year (+1 500 euros per dependent child, capped at 15 000 euros).

This tax credit is particularly advantageous as it benefits even non-taxable households (it is refunded by the Treasury).

Tax Reduction Investments

Several schemes allow you to reduce your tax by investing:

• Loi Pinel: 9 to 14 % reduction on the price of a new rental property, spread over 6 to 12 years
• FCPI/FIP: 18 % reduction on amounts invested in venture capital funds
• SOFICA: reduction of up to 48 % for film investment
• Girardin industriel: reduction that can exceed the amount invested (overseas one-off)

Timing Optimisation

Certain optimisation strategies rely on the timing of income and charges:

• Smooth exceptional income using the quotient system (Article 163-0 A of the CGI) to avoid jumping into a higher bracket
• Concentrate PER contributions in high-tax years (exceptional bonus, capital gain, final year of employment)
• Bring forward deductible charges (works on a rental property, PER contribution) in the year when your TMI is highest
• Defer income when possible (postponing a sale, staggering bonuses)

Special Cases and Subtleties

Withholding at Source

Since 2019, income tax has been withheld at source. The withholding rate is calculated based on the latest tax return. This mechanism does not change the amount of tax owed, but modifies the payment calendar.

Tax reductions and credits are still calculated during the annual return and result in a refund in summer. For recurring tax credits (home help, childcare), a 60 % advance is paid in January.

Separate vs Joint Returns

Married or civil partnership couples are required to file a joint return. In the year of marriage or PACS, they may opt for separate returns for the first year. In case of divorce or PACS dissolution, each former partner reverts to an individual return.

A joint return is advantageous when incomes are unequal. If both partners have similar and high incomes, the benefit of the spousal quotient is minimal.

Investment Income

Investment income (dividends, interest, capital gains) is subject by default to the Prelevement Forfaitaire Unique (PFU) of 30 % (12.8 % income tax + 17.2 % social contributions). The option for the progressive scale is possible but applies to all investment income.

The progressive scale option is advantageous when the TMI is 11 % or below and can also be beneficial at 30 % when factoring in the 40 % allowance on dividends.

Conclusion: Optimise Without Obsessing

Tax optimisation is a legitimate and rational approach that deserves to be integrated into any wealth strategy. However, it should never become the primary goal of an investment. A product that yields little but reduces your tax is not necessarily a good investment.

The best optimisation levers are often the simplest: contribute to a PER up to your ceiling, use home services, make charitable donations. These schemes combine tax advantages with personal or social utility.

For more advanced optimisation, consult a wealth management adviser who will analyse your overall situation and propose a coherent strategy, respecting the tax niche cap and tailored to your long-term goals.