France’s 2025 income tax filing season opened on 9 April 2026. Beyond the routine annual exercise, this year’s campaign introduces several significant changes that are particularly relevant for high-net-worth individuals. Between the renewal of the CDHR minimum tax, the restructuring of social contribution rates, and bracket adjustments, the stakes are high: a well-prepared return can mean a difference of tens of thousands of euros for a high-income household.

2026 Filing Calendar: Key Deadlines

The online filing service is available on impots.gouv.fr, now rebranded as « Mon espace Finances publiques ». The deadlines are as follows:

• 19 May 2026: deadline for paper returns.
• 21 May 2026 (11:59 PM): departments 01 to 19 and non-residents.
• 28 May 2026 (11:59 PM): departments 20 to 54.
• 4 June 2026 (11:59 PM): departments 55 to 976, including the Alpes-Maritimes (06), Var (83), and Bouches-du-Rhone (13) — covering the entire French Riviera.

For residents of the Cote d’Azur, the deadline is therefore 4 June. However, we strongly recommend starting your optimisation work well before this date.

The CDHR: Minimum Tax on High Earners Renewed

Introduced by the 2025 Finance Act as a temporary measure, the Contribution Differentielle sur les Hauts Revenus (CDHR) has been renewed for 2025 income. Its principle is straightforward yet powerful: it guarantees a minimum effective tax rate of 20% on the highest incomes.

The thresholds are:

• EUR 250,000 in reference taxable income for a single, widowed, separated, or divorced taxpayer.
• EUR 500,000 for a couple filing jointly.

In practice, if your income tax — combined with the exceptional contribution on high incomes and flat-rate withholdings on investment income — results in an effective rate below 20%, you will owe a top-up payment. This measure targets, in particular, taxpayers who optimise their tax position through the PFU (30% flat tax) on substantial capital income, paradoxically achieving a moderate overall tax rate.

Who is Actually Affected?

The most exposed profiles include:

• Business owners receiving significant dividends subject to the PFU.
• Holders of substantial financial portfolios with realised capital gains.
• Recipients of significant investment income (interest, bond coupons).
• Taxpayers combining moderate employment income with high investment income.

It is essential to simulate the CDHR impact before finalising your return. In some cases, opting for the progressive scale rather than the PFU may prove more advantageous — an analysis that must be conducted on a case-by-case basis.

Two CSG Rates: A Structural Change

The 2026 Social Security Financing Act introduces an unprecedented distinction in the CSG (Contribution Sociale Generalisee) rates applicable to investment income:

• Standard rate: 10.6%, applicable as a general rule to investment income and placement products (capital gains, dividends, interest).
• Reduced rate: 9.2%, applicable to certain income types, notably rental income.

This differentiation has a direct impact on property investors. A taxpayer earning EUR 100,000 in rental income benefits from a saving of EUR 1,400 compared to the full rate — far from negligible.

Updated Tax Brackets

The income tax brackets have been adjusted upward by 0.9% to offset inflation. While modest, this adjustment mechanically shifts all thresholds:

Additionally, the charitable donation tax relief cap for organisations helping people in difficulty rises from EUR 1,000 to EUR 2,000 (for donations made from 14 October 2025).

Furnished Rentals: New Rules to Watch

Non-professional furnished rental property owners (LMNP) need to pay close attention this year. The thresholds and standard allowances have been modified for 2025 income. If you own furnished rental properties — particularly on the Cote d’Azur, where seasonal rentals and managed residences are widespread — a thorough review is essential before validating your return.

Switching from the micro-BIC regime to the real expense regime may now be more advantageous depending on your situation. We recommend running a comparative simulation of both regimes.

Five Strategies to Activate Before Filing

For high-income taxpayers, here are the key optimisation areas to examine this year:

1. Simulate the CDHR impact. Calculate your overall effective tax rate to determine whether the top-up will apply, and evaluate possible trade-offs (progressive scale vs. PFU).

2. Optimise the mix of investment income. With two distinct CSG rates, the allocation between rental income and financial income has a direct tax impact.

3. Review all tax credits and deductions. Home employment, charitable donations, overseas investments, Denormandie scheme: ensure all applicable provisions are properly reported.

4. Choose between micro-BIC and real expense regime for furnished rentals. The updated thresholds may change the equation. A comparative simulation is essential.

5. Plan for the tax notice. If you owe more than EUR 300, payment will be spread over four monthly instalments from September to December. Factor this into your cash flow planning.

Payment Schedule

• 24 or 31 July 2026: potential refund of overpayment.
• 25 September 2026: single debit if the balance due is EUR 300 or less.
• September to December 2026: four monthly debits if the balance exceeds EUR 300.

Our Support

At Riviera Wealth Management, we assist our clients in preparing their income tax returns, in coordination with their accountants and tax lawyers. Our role is to ensure that the overall wealth strategy — asset allocation, structuring, estate planning — is accurately reflected in the return, and that all legitimate optimisations are activated.

The growing complexity of high-net-worth taxation — between the CDHR, dual CSG rates, furnished rental changes, and the multiplication of tax provisions — makes professional wealth management guidance more relevant than ever.

The information contained in this article is provided for informational purposes only and does not constitute personalised investment advice. Past performance is not indicative of future results.