France taxes investment income at a flat 31.4% by default. Ticking one box can lower that — but only if your overall income is modest. Here's how to know which option saves you money.
- France taxes dividends, interest, and capital gains at a flat 31.4% by default — you don't need to do anything to stay on this rate
- Ticking box 2OP switches everything to the sliding scale — which is cheaper if your overall income is modest, more expensive if it isn't
- It's an all-or-nothing decision — you can't apply it to dividends but not capital gains — so a large gain in the same year can wipe out any saving
- The impots.gouv.fr system will tell you which option is cheaper — but always verify it yourself by toggling the box on and off
Ticking box 2OP is simply telling the tax office: "Please ignore the flat tax and instead tax my investment income like it's a salary, because my overall income is low enough that it will save me money."
That is the whole decision in one sentence. Whether it actually saves you money depends on your income level — and on a few important details that catch people out.
For context on how social charges interact with this decision, see our guide to social charges in France. For the broader picture, see how the French tax system works.
The Default: What Happens If You Do Nothing
If you do not tick box 2OP, the system applies the flat tax (PFU) automatically.
In 2026, the flat rate is 31.4%, broken down as:
- Income tax: 12.8%
- Social charges: 18.6%
- Total: 31.4%
The flat rate applies automatically to bank interest, dividends, and capital gains from the sale of shares or securities. You do not need to do anything to stay on it — it is the default.
Note on the 2026 rate increase: The flat rate rose from 30% to 31.4% following an increase in social charges on investment income. This applies retroactively to 2025 income declared in spring 2026.
See the PFU / flat tax rates on the Taxpert reference data page →
When to Consider the Sliding Scale
The general rule: consider ticking 2OP if your income tax rate on regular income is 0% or 11%.
In 2026, the 11% band applies to taxable income up to €29,579 per household share. If your total taxable income per share is below this threshold, the sliding scale will almost certainly save you money on the income tax portion.
Worked Examples — €1,000 of Investment Income
| Income Type | Flat rate 31.4% | Sliding scale 0% band | Sliding scale 11% band |
|---|---|---|---|
| Bank Interest | €314 | €186 | €296 |
| Dividends | €314 | €186 | €252 |
| Capital Gains | €314 | €186 | €296 |
Why are dividends cheaper under the sliding scale at 11%? Under the sliding scale, dividends benefit from a 40% tax-free allowance — only 60% of your gross dividend is subject to income tax. On €1,000 of dividends: €600 taxed at 11% = €66 income tax, plus 18.6% social charges on the full €1,000 = €186. Total: €252 versus €314 under the flat rate.
Why is the 0% band so powerful? At 0%, ticking 2OP means you pay no income tax at all on investment income — only the 18.6% social charges. Every type of investment income costs €186 per €1,000 instead of €314. That is a saving of €128 per €1,000.
Important: Social charges are always due regardless of which option you choose. Box 2OP only changes the income tax portion (12.8%). It does not reduce or remove social charges. Only holding an S1 certificate affects your social charges rates.
The All-or-Nothing Rule — Why the Big Numbers Always Win
Box 2OP is an all-or-nothing decision. It applies to all investment income across your entire household — you cannot choose the sliding scale for dividends and the flat rate for capital gains.
Example of the conflict:
- €500 in dividends (sliding scale saves money — you are in the 11% band)
- €20,000 capital gain from selling shares (total income pushes you into the 30% band)
If you tick 2OP to save on the dividends, you simultaneously apply the sliding scale to the large capital gain — where 30% is far more expensive than the 12.8% flat rate. The dividend saving is wiped out many times over.
The rule: the big numbers always win the decision.
The Exception — The Quotient System
If you are facing a large, one-time capital gain, there is a mechanism that can change the calculation: the Quotient system.
This prevents a single large payment from pushing you into a much higher band by dividing that income across multiple years for tax calculation purposes. It only works on the sliding scale — so in some cases ticking 2OP and using the Quotient system together makes the sliding scale cheaper than the flat rate.
Most standard share sales don't qualify — the big numbers rule still applies. But if you have a significant one-off event, see our guide to pension lump sums and the quotient system.
Use the Simulation — It Is Reliable
The online filing system at impots.gouv.fr will often display a message at the end of your declaration if ticking 2OP would save you money. This simulation is generally reliable.
But do not rely on the message alone. Before you finalise:
- Note your current tax estimate
- Go back and tick box 2OP
- Check the new estimate
- Keep whichever is lower
Use the simulation — but verify it yourself rather than accepting the pop-up without checking.
The Hidden Saving — Using This Year's Social Charges Next Year
If you opt for the sliding scale, an additional benefit appears the following year.
6.8% of the social charges you pay this year becomes deductible from your taxable income next year. This is only available on the sliding scale — not available with the flat rate.
On €10,000 in dividends, €680 reduces your taxable income next year. In the 11% band, that is an extra €75 in tax savings — a hidden 1–2% discount on your effective rate.
Not life-changing in isolation. But it adds to the case for box 2OP for those on lower income levels.
Check Box 6DE: If you opted for 2OP last year, verify that this deduction has been carried forward correctly. It should appear on Form 2042, Section 6, Box 6DE.
Who Should Almost Never Tick 2OP
Anyone in the 30%, 41%, or 45% income tax bands should almost always stay with the flat rate.
The flat rate caps the income tax portion at 12.8%. Once your income pushes you into the 30% band — taxable income over €29,579 per share in 2026 — the sliding scale charges more than twice the income tax rate. The flat rate wins clearly.
The only exception worth investigating: dividends with the 40% allowance at the lower end of the 30% band. But this requires running actual numbers, not a rule of thumb.
Quick Decision Guide
| Your situation | Likely best option |
|---|---|
| Income tax rate 0% | Sliding scale (2OP) — save 12.8% on income tax |
| Income tax rate 11%, mainly dividends | Sliding scale (2OP) — 40% allowance makes it worthwhile |
| Income tax rate 11%, mainly interest or gains | Sliding scale (2OP) — likely cheaper, verify with simulation |
| Income tax rate 30% or above | Flat rate default — 12.8% beats 30%+ every time |
| Large capital gain + small other investment income | Flat rate default — big numbers win |
| Large one-off exceptional gain | Consider 2OP + Quotient system — run the numbers |
| Mixed portfolio, unsure | Use the impots.gouv.fr simulation |
Common Mistakes
-
Thinking box 2OP removes social charges. It does not. Social charges of 18.6% are due regardless. Box 2OP only affects the 12.8% income tax portion. Only an S1 certificate affects social charges rates.
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Not considering the all-or-nothing rule. Ticking 2OP applies to all investment income across your whole household. If you have a large capital gain alongside small dividend or interest income, the gain dominates. Calculate the total effect.
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Applying the 40% dividend allowance to social charges. The allowance reduces the taxable base for income tax only. Social charges are calculated on 100% of gross dividend income.
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Assuming last year's decision is right again this year. Your income mix changes. A year with a large capital gain should be assessed differently from a year with only interest and dividends. Check the simulation every year.
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Not using the impots.gouv.fr simulation. The system tells you which option is cheaper. Use it — and verify it manually by toggling 2OP on and off.
Frequently Asked Questions
What is box 2OP on the French tax return?
The option to waive the flat tax and have your investment income taxed under the sliding scale instead. You tick it voluntarily — and once submitted it is irrevocable for that tax year.
What is the flat tax rate in France in 2026?
31.4% — comprising 12.8% income tax and 18.6% social charges. An increase from 30% in previous years, applying retroactively to 2025 income.
Does ticking box 2OP reduce my social charges?
No. Social charges are due regardless of which option you choose. Box 2OP only changes the 12.8% income tax portion. Only an S1 certificate can reduce social charges rates.
Can I choose the sliding scale for dividends but keep the flat rate for capital gains?
No. Box 2OP is an all-or-nothing decision — it applies to all investment income across your entire household. You cannot mix and match by income type.
At what income level does the flat rate become better than the sliding scale?
As a general rule, once your income tax rate exceeds 11% — taxable income above €29,579 per household share in 2026 — the flat rate at 12.8% is almost always cheaper. At 30%, the flat rate saves you 17.2 percentage points on the income tax portion alone.
Is the impots.gouv.fr simulation reliable?
Generally yes. But verify it yourself by toggling 2OP on and off and comparing the total estimate. Do not rely solely on the pop-up message.