In brief
A married couple or civil partners (PACS) can have two different tax residences. The French tax authorities call this a “mixed couple” (couple mixte). The difference does not, by itself, mean that each spouse files a separate French tax return.
Where the spouses are married under a community property regime, they generally file a joint return. It covers all the income of the spouse domiciled in France and of dependants living in France, but only the French-source income of the spouse living abroad, where the applicable tax treaty gives France the right to tax it. The non-resident spouse's foreign income is excluded from the French tax base and ignored under the “effective rate” rule.
One practical point is often missed: the non-resident spouse may ask for an average tax rate on their French income where it is lower than the 20% and 30% minimum rates. For mixed couples, however, the relevant box does not appear in the online return, so the election has to be made by an express written statement.
Illustration
He accepts a position in London; she keeps her job in Lyon. The children stay at school in France, and so does the family flat. The following spring, the question arises in the most practical way: should they still file together, and which income should be declared?
Three questions must be kept apart, and they arise in this order. Where is each spouse tax resident? Is the couple still taxed jointly? Which income of each spouse falls within the French tax base?
What is a “mixed couple” for French tax purposes?
It is a married couple or civil partnership in which one partner lives in France and the other abroad. The expression comes from the French tax authorities themselves. It also covers a French civil servant posted abroad — treated as a French resident under Article 4 B(2) of the French Tax Code (Code général des impôts, or CGI) — whose spouse lives abroad.
Tax residence is assessed individually, for each member of the household. One spouse may therefore be a French tax resident while the other is not, even though they remain married or in a civil partnership.
Your spouse lives abroad: are you really a mixed couple?
Not necessarily. Working abroad does not automatically make someone a French non-resident. Where the spouse and children remain in France, the family home — the foyer under Article 4 B — may keep the departing spouse's tax domicile in France, even if they spend most of the year elsewhere. If the host country also treats them as its resident, the tax treaty decides between the two countries.
A mixed couple is therefore the result of that analysis, never its starting point. We explain how to determine each spouse's tax residence when the family has stayed in France in our article “Working Abroad While Your Family Remains in France: Are You Still a French Tax Resident?”.
Conversely, two spouses can live in different countries without forming a mixed couple. A French civil servant posted abroad and a spouse who remains in France are both French tax residents, taxable in France on their worldwide income, including pay earned abroad.
One joint return or two separate returns?
Joint taxation of spouses and PACS partners is the rule. Article 6 of the French Tax Code allows separate taxation only in limited cases: spouses married under a separation of property regime who do not live under the same roof; spouses authorised to live apart during separation or divorce proceedings; and desertion of the marital home where each spouse has separate income.
Leaving aside separation or divorce proceedings and desertion of the marital home, a mixed couple will in practice be in one of two situations.
Under a community property regime, the couple generally files a joint return with the tax office of the spouse domiciled in France.
Under separation of property, where the spouses no longer live under the same roof, each spouse files their own return: the resident spouse with their local tax office, the non-resident spouse with the tax office for non-resident individuals (Service des impôts des particuliers non-résidents). Each then receives a separate tax notice, one as a resident, the other as a non-resident.
The separate residence must be genuine. The French tax authorities' official guidance (BOFiP) treats it as triggering separate taxation only where it is not temporary, and working abroad is not enough in itself. In a 2011 case, the Conseil d'État upheld joint taxation for spouses married under separation of property: the husband had work-related accommodation in Saudi Arabia but regularly returned to the house the couple owned in France (CE, 21 October 2011, no. 333898).
Which income goes on a mixed couple's joint French return?
The joint return does not treat both spouses alike. The French tax authorities set out its content in their guidance on mixed couples (in French).
The spouse domiciled in France declares all their income, from French and foreign sources, together with that of dependants living in France. Tax treaties and their double tax relief mechanisms then apply item by item.
The spouse domiciled abroad declares only French-source income, and only where the treaty allocates taxing rights to France. Their foreign income stays outside the French tax base.
Back to the London–Lyon couple. She, a French resident, declares her Lyon salary and the dividends received on a securities account held abroad. He, a UK resident, does not declare his London salary. He does, however, declare the rent from the flat he lets in Bordeaux: income from real property is taxable in the country where the property is located, a rule found in the France–UK tax treaty, as in most treaties concluded by France.
Does the non-resident spouse's foreign income affect the tax rate?
Not for the household's tax: it is excluded from the base and ignored for the effective rate rule.
The non-resident spouse's French income, however, follows its own rule. Under Article 197 A of the French Tax Code, it is in principle subject to a minimum tax rate for non-residents: for 2025 income, 20% up to €29,579 of net taxable income and 30% above that amount. The non-resident spouse may instead ask for an average rate, calculated on the household's worldwide income, which applies only if it is lower.
This is where couples get caught out. In a mixed couple's online return, the box to opt for the average rate does not appear. The election must therefore be made by an express statement in the “Informations” section at the end of the return, before signing, listing the foreign-source income to be taken into account. Otherwise, the minimum rate is likely to apply.
If the tax notice ignores the election, avoid correcting the return online, which may reproduce the error. The French tax authorities recommend a claim through the secure messaging service of your online account, with supporting documents, in particular the tax assessment issued in your country of residence.
Does the non-resident spouse count towards the household's tax shares?
Yes, and the BOFiP is explicit on this point: their foreign income leaves the tax base, but they remain part of the household: the couple keeps the number of tax shares (parts) of a married or PACS couple under the quotient familial system.
Family status is declared as it stands on 1 January of the tax year, and a spouse must be declared even if never known to the French tax authorities. If they have no French tax number, the return must be filed on paper (form 2042), with their civil status details and copies of an identity document and of the marriage certificate, PACS registration or family record book; a tax number is then assigned. For a French national who married abroad, the marriage must also have been transcribed in the French consular civil registers to be recognised by the tax authorities.
Does a mixed couple affect the French real estate wealth tax (IFI)?
Yes, and it is assessed person by person.
The €1.3 million threshold applies at household level, including the spouse or partner. But, under the French tax authorities' official guidance, real estate located outside France is included only for household members personally domiciled in France. The non-resident spouse therefore brings in, in principle, only real estate located in France, including the portion of shareholdings that represents such property.
As for income tax, spouses married under separation of property who do not live under the same roof are assessed to IFI separately.
What to check before filing
The order of the questions matters as much as the answers:
Each spouse's tax residence for the year, taking into account the date of any departure or return.
The applicable tax treaty, in the event of dual residence and for each category of income.
The matrimonial property regime, whether the couple actually lives together and any separation or divorce proceedings, which decide whether joint taxation continues.
The source of each item of income, and which country the treaty allows to tax it.
Whether the average rate is worth claiming, by express statement.
IFI, where the household's real estate approaches the threshold.
The year of departure or return concentrates most of the difficulties: residence changes during the year and income must be split between two periods.
Where one spouse has recently moved abroad, or French income remains on both sides, the return is best prepared before it is filed: correcting a return is always more burdensome than filing it right.
Beaupère & Guermouche Avocats advises couples whose spouses do not share the same tax residence, when one of them leaves France, when the family returns, or when preparing their French tax returns.
Frequently asked questions
What is a mixed couple for French tax purposes?
A married couple or civil partnership in which one partner is a French tax resident and the other is not. Tax residence is assessed for each spouse individually.
My spouse works abroad: are we automatically a mixed couple?
No. If the family lives in France, your spouse may remain a French tax resident despite working abroad. Their residence is determined first under French domestic law and then, where relevant, under the tax treaty.
Does a mixed couple have to file two French tax returns?
Not necessarily. Different tax residences are not enough: two returns are required only in the cases set out in Article 6 of the French Tax Code, in particular for spouses married under separation of property who do not live under the same roof, or spouses authorised to live apart during separation or divorce proceedings. Otherwise, a couple married under a community property regime generally files jointly.
We are married under separation of property and my spouse works abroad: must we file separately?
Not merely because of the move abroad. For spouses married under separation of property, separate taxation requires that they no longer live under the same roof on a lasting basis: regular returns to the shared home may be enough to keep joint taxation.
Is my non-resident spouse's foreign income taxable in France?
In principle, no. It is excluded from the tax base and from the effective rate calculation. Only French-source income that the treaty allows France to tax goes on the return.
How do we claim the average tax rate for my non-resident spouse's French income?
By an express statement in the “Informations” section at the end of the online return, listing their foreign-source income: the usual box does not appear for mixed couples. If the tax notice ignores it, a claim through secure messaging is preferable to an online correction.
Does my non-resident spouse count towards the number of tax shares?
Yes. They remain part of the household for the quotient familial, even though their foreign income is excluded from the tax base.
The rules described in this article are general. The tax treatment of a mixed couple depends on each spouse's tax residence, their matrimonial property regime, the source of their income and the applicable tax treaty.