Tax Residence: How the French Tax Authorities Reason
By Eve d'Onorio di Meo — Tax Lawyer, Marseille and Geneva Bars
Tax residence is the cornerstone of any expatriation. It determines in which State you are taxable on your worldwide income. And it is precisely on this ground that Franco-Swiss disputes are most frequent and most bitterly fought. Understanding how the French tax authorities build their reasoning is essential to securing a move to Switzerland over the long term.
Step 1 — French domestic law: Article 4B of the CGI
Before applying the bilateral treaty, the DGFiP checks whether you meet one of the three alternative criteria of Article 4B of the French Tax Code. Meeting a single criterion is enough to make you a French tax resident:
— Home or main place of abode in France: you have accommodation in France (owned, rented, occupied free of charge) and stay there as your main residence.
— Main professional activity in France: your employed or self-employed activity, carried on in France, represents the bulk of your economic activity.
— Centre of economic interests in France: your major investments, the seat of your business, or the centre of your economic activities are located in France.
These criteria are alternative and assessed on the facts. Legal form — a notarised deed of sale, a lease signed in Geneva — is not enough if the facts tell a different story.
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Step 2 — The Franco-Swiss treaty: the tie-breaker cascade
If you are regarded as resident by both States at once, the bilateral treaty of 9 September 1966 (amended in 1969, 1997 and 2009) provides a cascade of four criteria applied in the following strict order:
Criterion 1 — The permanent home
Residence is attributed to the State in which you have a permanent home — a dwelling you have arranged and keep for your lasting use. If you have a permanent home in each State, the centre of vital interests is examined: the State with which your personal and economic relations are closest.
Criterion 2 — Habitual abode
If the centre of vital interests cannot be established, residence is attributed to the State in which you stay most frequently. This is not an automatic 183-day threshold — it is an overall, qualitative assessment of the frequency and length of stays in each country.
Criterion 3 — Nationality
If you have a habitual abode in both States, nationality determines residence. A person holding only French nationality will then be regarded as a resident of France.
Criterion 4 — Mutual agreement
As a last resort, the tax authorities of the two States may settle the question by mutual agreement — a rare route, but one that exists for the most complex cases.
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How the DGFiP investigates an expatriation file
The authorities never rely on a single indicator. They build a body of evidence. The items systematically requested during an audit:
— Bank card statements: geographic location and frequency of spending over 12 to 36 months
— Mobile phone bills: geolocation of calls and connections
— Travel records: SNCF, Air France, easyJet tickets, with dates and destinations
— Medical documents: GP, prescriptions, French health insurance reimbursements
— Children's schooling: enrolment certificates in France or Switzerland
— Insurance contracts: declared location of risk for home, vehicle, health
— Social media: geolocation of posts, check-ins, localised interactions
Case study — Emmanuel, an IT consultant, declares that he has lived in Geneva since 2020. The DGFiP notes: card payments in Paris shops 4 to 5 days a week, membership of a Paris gym, GP in the 8th arrondissement, children enrolled at the Lycée Janson-de-Sailly. His Geneva flat at CHF 4,500 a month is not disputed — but his actual presence in France is documented. Reassessment: French residence reinstated for 2020, 2021 and 2022. Back taxes: €380,000.
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The burden of proof and the evidence file
Formally, it is for the authorities to prove that you are a French resident. In practice, once they have assembled a serious body of evidence, the burden shifts: it is for you to demonstrate that your Swiss residence is genuine. Hence the importance of building an evidence file from the very first day of your move to Switzerland:
— Swiss lease or title deed dating from the start of the move
— Local utility and consumption bills (electricity, internet, subscriptions)
— LAMal health insurance certificate and AVS number obtained
— Registration with the Swiss commune (residents' register)
— Active Swiss bank accounts used day to day
— Evidence of physical presence (SBB travel passes, sports clubs, local associations)
Point of attention — Since 2024, the DGFiP has used automated data-matching algorithms to identify fictitious non-residence. Google Pay, Apple Pay, Amazon, Netflix, Spotify: the geolocation of your digital spending is an irrefutable footprint of your actual presence.
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FAQ — Frequently asked questions
What is the centre of vital interests under the Franco-Swiss treaty?
The centre of vital interests is the place where your personal and economic relations are closest: location of the family home (spouse, children), professional activities, assets, social and community life. It is an overall criterion, not an arithmetical one.
Does a Swiss tax residence certificate protect against a French reassessment?
No, not automatically. The French authorities may challenge the Swiss certificate if they consider that the criteria of the Franco-Swiss treaty are not met. The certificate is a strong but not decisive indicator. Only the reality of the facts prevails.
How many days can you spend in France without losing your Swiss residence?
There is no statutory 183-day threshold in the Franco-Swiss treaty. It is habitual and predominant presence that is assessed overall. In practice, beyond 150 to 180 days a year in France, the risk of recharacterisation is high — especially if your economic interests remain concentrated there.
Does the Franco-Swiss treaty also apply to wealth tax?
Yes. The Franco-Swiss treaty of 9 September 1966 covers both income tax and wealth tax. The residence attribution rules apply to both types of tax.
What is the CRS automatic exchange of information and how does it affect my file?
Since 2018, Swiss banks have automatically transmitted to the DGFiP information on the bank accounts of clients declaring French residence (Common Reporting Standard). If your Swiss accounts show a French address even though you have declared your departure, an alert is generated. This is the main trigger for expatriation audits.
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Contact us
Reply within 48 hours for an audit of your file.
📞 +41 22 320 42 42
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Eve d'Onorio di Méo
Lawyer, Certified Specialist in Tax Law
Member of the Marseille Bar (France) and of the Geneva Bar Register (Switzerland)
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