ISA Taxation in France: What British Expats Need to Know

“It’s still called an ISA, but the tax benefits don’t travel with you.”

Many UK residents are rightfully proud of their ISA portfolios. They’re simple, flexible, and tax-free. But if you’ve moved to France — or are planning to — your ISA may not be as tax-efficient as you think.

This article explains how France treats ISAs, what kind of tax liabilities can arise, and why proper planning is key.

The Scenario: A Common (and Costly) Surprise

Let’s say:

  • You began contributing to ISAs in 2001, investing £220,000 over the years.

  • By January 1, 2020, when you became tax resident in France, your ISA was worth £410,000.

  • Now, in July 2025, it’s grown to £475,000.

  • You want to withdraw the funds to help your children buy a home.

So what’s the tax bill in France?

€19,955

France Doesn’t Recognise the ISA Wrapper

This is the critical point: France treats your ISA as a regular foreign investment account.

That means:

📌 No tax protection — Dividends, capital gains, and interest are fully taxable
📌 Income is taxed annually, even if you reinvest it inside the ISA
📌 You must report the account each year using Form 3916
📌 All reporting must be in euros, using the exchange rates on the transaction dates

“France views the ISA as if it’s just another brokerage account held abroad.”

What Happens When You Sell Your ISA

Here’s what the calculation looks like — based on actual exchange rates:

GBP/EURValue at French tax residency (Jan 2020)£410,000/€479,700 (GBP/EUR 1.17)

Value at sale (July 2025)£475,000/€546,250 (GBP/EUR 1.15)Taxable gain—€66,550

French flat tax (“PFU”) at 30% applies:

  • 12.8% income tax = €8,518

  • 17.2% social charges = €11,437

  • Total tax due = €19,955

The Reporting Burden Adds Up

Even if you don't withdraw any funds, you're still expected to declare:

  • All dividends or interest earned annually

  • Any capital gains realised within the ISA (e.g. if a fund is sold)

  • All values in euros, not pounds — adding FX exposure to your tax position

“French tax is based on the value change in euros — not pounds — which means FX moves can increase your taxable gain even if your ISA barely moved in GBP terms.”

What You Can Do About It

At MiraClair Wealth, we regularly advise clients who hold UK ISAs what to do. Here’s what we recommend:

  • Consider realising gains before becoming French tax resident

  • For a more tax-efficient structure? Read our article on Assurance Vie in France

  • Use a currency-aware investment strategy

  • Get help with proper reporting

"If you still have an ISA and are already tax resident in France, the sooner you review it, the more options you may have."

Important Information


The information on this page is for general guidance only and does not constitute personal financial, tax, or investment advice. Tax treatment depends on individual circumstances and may change in the future. Cross-border planning should always be reviewed with a qualified professional who understands both UK and French regulations.

If you are considering making any changes to your pension or investments, we strongly recommend seeking personalised advice.

Talk to Us

Every situation is unique. If you’ve moved to France and hold an ISA — or are planning to — we can help you understand:

  • What your actual exposure is

  • Whether action is needed

  • How to optimise your cross-border wealth strategy

👉 Book a cross-border investment review with MiraClair Wealth today.