The concept of tax residency — the foundation upon which personal income taxation is built in virtually every developed country — is under more scrutiny than at any point in modern history. Governments across Europe, North America, and Asia-Pacific are investing heavily in tools, treaties, and enforcement mechanisms designed to ensure that individuals who claim to have left their home countries have genuinely done so.

For international entrepreneurs, consultants, and high- net-worth individuals, the implications are direct and increasingly urgent.

Why governments are tightening enforcement

The motivation is fiscal, but it is also political. As wealth inequality has become a prominent political issue across Western democracies, the perception that wealthy individuals can simply relocate to avoid taxation has generated significant public backlash. Governments have responded with both legislative action and increased enforcement budgets. The numbers are significant. France's Direction Générale des Finances Publiques (DGFiP) has increased its international tax audit capacity by approximately 30% since 2020.

The UK's HMRC has designated a specialised Wealthy Compliance Unit focused on high-net-worth individuals with international arrangements. Italy's Agenzia delle Entrate has developed specific protocols for challenging claimed departures to low-tax jurisdictions, particularly the UAE, Portugal (under the former NHR regime), and Switzerland. The tools available to these authorities have expanded dramatically.

The automatic exchange of financial information through CRS provides tax authorities with data on accounts held by their residents in foreign jurisdictions — without the need for a specific request. Air travel records, obtainable through bilateral cooperation agreements, can establish patterns of physical presence. Credit card transaction data, mobile phone location records, and social media activity have all been cited in tax residency proceedings across multiple jurisdictions.

France: the Article 4B framework

The French framework for tax residency is among the most aggressive in the world. Article 4B of the Code Général des Impôts establishes four independent criteria for tax residency. An individual who meets any single criterion is considered a French tax resident and is subject to taxation on their worldwide income. The four criteria are: (a) having one's foyer or principal place of stay in France — interpreted broadly to include the place where the individual's family habitually resides, regardless of the individual's own physical presence; (b) exercising one's principal professional activity in France — the location where the individual actually and regularly performs their work; (c) having one's centre of economic interests in France — the place where the individual's principal investments are located, where they administer their assets, or where they derive the majority of their income; and (d) being an agent of the French State posted abroad.

The interaction with the France-UAE tax convention is particularly important. Unlike most bilateral tax treaties, which provide tie-breaker rules to resolve dual residency in favour of one country, the France-UAE convention (signed July 19, 1989) contains an anti-abuse provision in Article 19.2 that effectively allows France to reassert full taxing rights if any of the Article 4B criteria are met. This means that the conventional protection for French nationals in the UAE is significantly weaker than in most other treaty relationships.

The implications are practical. A French entrepreneur who relocates to the UAE but maintains a property in France where their spouse and children continue to reside may be considered a French tax resident under criterion (a). One who continues to manage a French-based business remotely may be caught by criterion (b). One who retains significant French investments — real estate portfolios, securities accounts, business participations — may fall under criterion (c).

United Kingdom: the Statutory Residence Test

The UK Statutory Residence Test (SRT), introduced in Finance Act 2013, provides a more structured but no less complex framework. The SRT operates through a series of automatic tests (both overseas and UK) and, if no automatic test is conclusive, a sufficient ties test that evaluates the individual's connections to the UK against their days of physical presence. The ties considered are: a UK-resident family (spouse, civil partner, minor children), accessible UK accommodation, substantive UK work (40 or more days), presence in the UK in either of the two preceding tax years for more than 90 days, and more days in the UK than in any other single country.

The number of ties required to establish UK residency decreases as the number of UK days increases. For individuals who have been UK resident in one or more of the three preceding tax years, the bar is lower. As few as 16 days in the UK can be sufficient to establish residency if four or more ties are present. The SRT's complexity creates both risks and opportunities. Individuals who manage their ties carefully and monitor their days of presence can achieve a clean departure.

But the margin for error is narrow, and HMRC's enforcement capability has increased significantly with the introduction of passenger locator data, border crossing records, and digital tracking tools.

The role of professional substance

Across jurisdictions, one element consistently emerges as the most important — and most defensible — indicator of genuine relocation: professional substance in the new country of residence. An individual who is formally employed in their new jurisdiction, with a government-certified contract, a regulated salary, and institutional recognition from the local labour authority, has the strongest possible evidence of professional activity in that jurisdiction.

This is not a theoretical argument. It is the standard used by multinational corporations when relocating their executives — and it is recognised by tax authorities worldwide as a significant indicator of genuine residency. The evidentiary value of this professional substance is threefold. First, it directly addresses the professional activity criterion (criterion (b) in France, the substantive work tie in the UK).

Second, it creates a documented, traceable record of presence and economic activity in the new jurisdiction. Third, it signals to tax authorities that the relocation is genuine — that the individual is not merely maintaining a postal address while continuing to live and work elsewhere. For entrepreneurs and independent professionals, accessing this kind of professional infrastructure has historically been challenging.

Large corporations have dedicated mobility teams and local entities in dozens of countries. Independent professionals typically do not. But the mechanisms are the same, and the legal effect is identical. What matters is the substance of the arrangement, not the size of the employer.

Conclusion

At Fidelys Partners, we help clients navigate tax residency transitions with the precision and documentation that modern enforcement environments demand. Every element of the relocation — professional activity, financial arrangements, family considerations, administrative registrations — is structured to be defensible under the specific rules of the departing and arriving jurisdictions. In a world of increasing scrutiny, hope is not a strategy. Substance is.

— Fidelys Partners —