The word is formed from aubain, a foreigner, which Gilles Ménage derived further from the Latin alibi natus; Jacques Cujas derived from advena; and du Cange from albanus, a Scot or Irishman, by the reason that these were anciently frequent travelers living abroad.
The opposite of an aubain was a régnicole, someone who died outside the French kingdom but was a royal subject by birth and residence.
[1] In the Ancien Régime, aubaine was a right of the King of France, allowing him to claim the inheritance of all foreigners in his dominions; exclusive of all other lords, and even of any testament the deceased could make.
The Swiss, Savoyards, Scots, and Portuguese were also exempted from aubaine, as they were considered naturalized.
To give them security while generating state revenue, the right of aubaine was transformed into a tax on foreigners: for a 5% tax on the value of the property of the deceased, the king waived his right of aubaine for the nationals of Geneva (1608), Holland (1685), England (1739), Denmark (1742), Naples, Spain and other Bourbon lands in Europe (1762), the duchy of Tuscany (1768),[2] and the duchy of Parma[3] (1769).