In two stages. First the domestic law of each State. In France, Article 4 B sets out four alternative tests: your household, your main place of stay, professional activity carried on other than as an ancillary activity, and the centre of your economic interests. Any one of them is enough to make you resident. If the other State also treats you as resident under its own rules, the bilateral treaty then decides, through a tie-breaker applied in order: permanent home, centre of vital interests, habitual abode, then nationality. The test available above on this page follows that logic.

Article 167 bis applies to individuals who have been French tax residents for at least six of the ten years preceding the transfer of residence, and who on the date of departure hold either shareholdings worth more than 800,000 euros in total, or a holding representing more than 50% of the profits of a company. The residence condition and one of the two thresholds must both be met. Timing against a sale is usually the decisive question, not the tax itself.

Twelve to twenty-four months where business assets are involved. The reason is not administrative but chronological: a gift to children, a holding restructuring or the choice between selling before or after departure do not produce the same effects depending on the order in which they happen, and some options close permanently once residence has moved. A departure decided three weeks before the move leaves very little room.

No. Article 155 B requires you to take up salaried employment or a corporate office in a company established in France, either at that company's request or through direct recruitment from abroad. It also requires that you were not a French tax resident during the five preceding calendar years. Moving back as a self-employed worker, as a retiree, or without that kind of professional framework does not open the right. Hence the value of a review six to twelve months before the move.

The taxation splits. The acquisition gain is generally allocated to the period during which the underlying activity was carried on, which means apportioning it between the States concerned in proportion to that period. The capital gain on sale, by contrast, normally follows the State of residence on the date of sale. Each treaty has its own allocation rules, and the characterization adopted by the country of grant does not bind France. A reading done before the sale avoids a double taxation that is very hard to unwind afterwards.

The general treaty rule is that employment income is taxable in the State where the work is physically performed, with an exception for short assignments resting on three cumulative conditions: fewer than 183 days of presence, an employer not resident in that State, and remuneration not borne by a permanent establishment located there. Durable remote work removes that exception. On top of this sits the question of social security affiliation, which follows rules distinct from those of income tax and is settled beforehand, not after the fact.