The day you put your bags down in France, your wealth does not move by a cent. Your taxation changes completely. That gap is what catches people out: nothing looks different, yet you have just switched systems, with new obligations that sometimes apply from the year of return itself.
Here is what changes, and above all in what order to handle it.
First: from when are you a French tax resident?
Everything flows from this question, and the answer is not "when I say so". Article 4 B of the French tax code sets out alternative criteria: meeting one is enough.
You are a French tax resident if your home (spouse, children) or main place of stay is in France, or if you carry out your main professional activity there, or if France is the centre of your economic interests.
Two consequences people underestimate. First, the home criterion can make you resident before your own move, if your family returns months ahead of you. Second, if another country also treats you as resident, you do not settle the conflict: the bilateral tax treaty does, through its cascade of tie-breakers (permanent home, centre of vital interests, habitual abode, nationality).
On the day you return, record the exact date and keep the evidence: employment contract, lease, tickets, foreign cancellations. If questioned, that file is what counts.
The switch: from territorial to worldwide taxation
This is the major change. As a non-resident you were taxable in France only on French-source income. As a resident you become taxable in France on your worldwide income, subject to treaties that prevent double taxation.
In practice, everything that was off the radar no longer is: dividends from a brokerage account left in London, interest on an American account, rent from a property abroad, capital gains, crypto income.
The year of return is a special one: it is generally split into two periods, before and after settling, with distinct rules. It is not the year to file in a hurry.
Accounts left abroad: the omission that costs the most
Once you are resident, every account held outside France must be declared (form 3916, and 3916-bis for digital-asset accounts with a foreign provider), whether or not it produces income.
The fine is €1,500 per account per non-time-barred year, rising to €10,000 for a state with no administrative assistance agreement. It is due even for an empty account.
This is the classic post-expat mistake: keeping the old current account "just in case", forgetting the local payment app or the brokerage account never closed. Make the exhaustive list, including accounts closed during the year.
Share plans and stock options: the technical one not to improvise
If you were granted free shares or stock options, or joined an employee share plan abroad, the tax treatment often depends on where you were during the vesting period, not only where you are when you sell.
Some treaties split taxing rights pro rata to time spent in each country. The result can be taxation shared between two states, with a tax credit to avoid double taxation, and calculation rules that differ by plan type.
This is exactly the case where what you save by consulting a tax lawyer far exceeds their fee. Do not improvise it.
Swiss second pillar and foreign pension schemes
If you worked in Switzerland, your occupational pension (LPP) holdings follow their own rules. What happens to a lump-sum payment, how it is taxed in France, and whether to leave the holdings on a vested-benefits account rather than repatriate them: each option has different consequences, and the right choice depends on your situation and timing.
The same logic applies to an American 401(k), a UK pension or a Luxembourg scheme. The common thread: when you transfer often matters more than how much.
The order to tackle it in
1Establish and document the residence date
Everything else follows from it: it decides what falls inside the French scope.
2List every foreign account
Active or closed during the year, neobanks and crypto platforms included.
3Inventory your worldwide wealth
With currency and value: securities, property, pensions, share plans, cash.
4Identify the treaty-driven topics
Share plans, pensions, property abroad. Those are the ones that justify a professional.
5Check the favourable regimes
The impatriate regime (article 155 B) notably requires not having been a French tax resident during the five preceding calendar years. It is checked before the move.
Prepare the return-year filing
Without rushing: it sets the pattern for every year that follows.
The order is not cosmetic. The residence date sets the scope of everything else, and step five plays out before the move: checked afterwards, it is already lost.
The underlying trap
The real risk when moving back is not paying too much tax. It is not knowing what you own, because the wealth was built across three countries, four currencies and six institutions, without ever being looked at as a whole.
Until that overview exists, no tax or wealth decision can be taken seriously, and reporting obligations get discovered as you go, usually a beat too late.
Where IgniFI comes in
That is exactly the starting point: consolidating scattered wealth. IgniFI brings your accounts together whatever their currency and location, converted to euros at current rates, with a single view of what you actually own.
These are prepared figures, not tax advice: for share plans, foreign pensions and the impatriate regime, take a professional. But walk in with your numbers straight and you will be better off on every count.