I'm French, working in US tech — what taxes apply when I move back to France?
Short answer: French residents are taxed on their worldwide income. Under the US–France tax treaty, a 401(k) or IRA paid to a French resident who is not a US citizen is taxable only in France, while US Social Security stays taxable only in the US. On return you must declare every US account (Form 3916), pay French tax on US dividends and gains (the 31.4% flat tax from 2026), and plan RSU vests that straddle the move.
Written and reviewed by Anthony Walsh, Selanis. Last reviewed 2026-10-06.
Why it works this way
Article 18 of the US–France treaty splits the two main US retirement incomes. Private pensions such as 401(k) and IRA distributions paid to a French resident are taxable only in France (the US 'saving clause' keeps US taxing rights only over US citizens and green card holders). US Social Security paid to a French resident is taxable only in the US, but France still counts it when setting your rate (taux effectif).
French residency (résidence fiscale) restarts the day you arrive with the intent to stay. You will need to file Form 2042 for your French-sourced income and Form 2047 for your foreign-sourced income. Importantly, France requires the declaration of all foreign bank accounts (Form 3916), including your US brokerage and retirement accounts.
US-domiciled ETFs and mutual funds are a specific challenge. France's flat tax (Prélèvement Forfaitaire Unique, PFU) on dividends and gains rose from 30% to 31.4% for 2026 income, after the 2026 social security budget raised the CSG on capital income. An assurance vie can be more tax-efficient after eight years, but EU product rules (PRIIPs) mean it cannot hold US-domiciled ETFs, so the wrapper and the US portfolio need to be planned together.
The expensive mistake: Forgetting to declare US accounts on Form 3916
France imposes strict penalties for failing to declare foreign bank accounts and life insurance policies. Even if there is no tax due on the account growth, the simple failure to list your US accounts on your annual French tax return can result in significant per-account fines.
What to do
- Register with the French tax authorities — Inform the 'Service des Impôts des Particuliers' (SIP) of your return and set up your online account at impots.gouv.fr.
- Review your US equity vesting schedule — French 'social charges' (CSG/CRDS) can be high. Ensure you understand how France will tax the portion of RSUs that vest after you arrive.
- Seek a 'bilan patrimonial' for your US assets — Before you move, check how your US portfolio will be taxed in France. The wealth tax (IFI) only covers real estate worth more than €1.3M, including a US home you keep.