7 Tax Mistakes That Cost French Investors Thousands of Euros

In France, investment taxation is among the most complex in Europe. The result: thousands of investors make mistakes every year that cost them hundreds, even thousands of euros. These errors don't come from poor investment strategy. They come from a lack of knowledge about the tax rules. Here are the 7 most costly ones.

Mistake 1: Withdrawing from the PEA before 5 years

This is the most costly and most widespread mistake. Many investors open a PEA, invest €10,000, and 3 years later need money for a project. They withdraw their capital. The consequences:

• The PEA is automatically closed (before 5 years, any withdrawal = account closure)
• Gains are taxed at the flat tax of 31.4% instead of the 18.6% that would apply later
• You lose your opening date and must start from zero with a new PEA

Concrete example: you invested €10,000 and your PEA is worth €14,000 after 3 years. You withdraw everything. Gains: €4,000. Tax: €4,000 × 31.4% = €1,256. If you had waited 2 more years (5 years total) with the same value: €4,000 × 18.6% = €744. Difference: €512 lost for 2 years of impatience.

The golden rule: money in a PEA must be money you don't need for at least 5 years. If you might need it sooner, keep it in a savings account. For full rules, see our PEA tax guide.

Mistake 2: Opening the PEA too late (or not opening it at all)

The 5-year clock starts at the date the PEA is opened, not at the date of your first significant deposit. If you open a PEA on 15 June 2026 with €100 and add nothing else for 3 years, then start investing seriously in 2029, you enter the favourable tax regime on 15 June 2031.

If you wait until 2029 to open your PEA, you don't reach the PEA tax regime until 2034. That's 3 additional years of being taxed at 31.4% instead of 18.6%.

The action to take: open your PEA today, even with €100, if you haven't already. It takes 30 minutes and starts the clock immediately.

Mistake 3: Not using the life insurance allowance after 8 years

If you have a French assurance-vie (life insurance) policy held for more than 8 years, you benefit from a tax allowance of €4,600/year on gains (€9,200 for a married or civil partnership couple). What most people don't know: this allowance cannot be carried over and is lost if not used each year.

Example: you have a life insurance policy with €80,000 in unrealised gains after 8 years. Each year, you could withdraw enough to generate €4,600 in gains exempt from income tax (only 18.6% social contributions apply). If you fail to do this for 5 years, you lose 5 × €4,600 = €23,000 in allowances.

Tax saved if you use the allowance every year: €23,000 × 12.8% = €2,944 in income tax saved over 5 years. That's money left on the table every year through inaction.

The correct strategy: make a partial withdrawal each year to use the allowance, then immediately reinvest if you don't need the funds. See our assurance-vie guide for details.

Mistake 4: Selling in December instead of waiting for January

Want to rebalance (sell one ETF to buy another) or realise capital gains? The date matters. A sale on 28 December generates a taxable gain in the same tax year. A sale on 3 January falls into the next tax year: you defer the tax by a full year.

This tax deferral isn't trivial. If you have €5,000 in flat tax to pay: you can keep that €5,000 invested for another 12 months at 7% and earn approximately €350 in additional return before paying the taxman. It's not tax evasion, it's perfectly legal timing optimisation.

Rule to remember: barring absolute urgency, never make a sale with significant capital gains in December. Wait until January.

Mistake 5: Putting savings in a CTO when the PEA isn't full

The PEA accepts up to €150,000 in contributions and offers 18.6% taxation after 5 years. A regular brokerage account (CTO) taxes gains at 31.4% flat tax. Yet many investors open a CTO alongside their PEA while their PEA isn't full, "for more flexibility."

On €100,000 in gains, the tax difference is 31.4% - 18.6% = 12.8 percentage points. That's €12,800 paid in extra taxes compared to the PEA solution.

The rule: fill the PEA first (up to €150,000 in contributions). When it's full, open a life insurance policy (assurance-vie) with ETFs as unit-linked options. The CTO is only relevant for assets ineligible for the PEA (non-UCITS ETFs, certain structured products, etc.). See our PEA vs CTO comparison.

Mistake 6: Not declaring foreign accounts (Trade Republic, Revolut)

Trade Republic is a German bank. Revolut is based in Lithuania. Degiro is Dutch. All these foreign brokers must be declared annually on form 3916 (alongside your income tax return).

The penalties:

• Fine of €1,500 per undeclared account (per year)
• Fine of €10,000 if the country is non-cooperative for tax purposes
• Possible tax reassessment with an 80% surcharge in cases of wilful fraud

The good news: Trade Republic has been automatically providing an IFU (French tax certificate) to French tax residents since 2022. But the account declaration via form 3916 remains mandatory separately. For details, see our CTO tax guide which also covers foreign brokers.

Mistake 7: Confusing the PEA contribution ceiling with portfolio value

The PEA has a ceiling of €150,000 in contributions (money entering the account). The portfolio value can legally exceed €150,000 thanks to gains. A PEA with €150,000 in contributions and €250,000 portfolio value is perfectly legal.

The classic mistake: thinking that when the portfolio is worth €160,000, you've "exceeded the ceiling" and stop contributing. Wrong. What counts is the total cash deposited, not the value of securities in the portfolio.

The other mistake: believing that withdrawing then re-depositing "frees up space" in the PEA. Wrong. Contributions made count permanently, even if you withdraw them. You cannot "recycle" the PEA ceiling.

Frequently asked questions