The Collaborative International Dictionary of English v.0.48:

Aubaine \Au`baine"\, n. [F., fr. aubain an alien, fr. L. alibi
   elsewhere.]
   Succession to the goods of a stranger not naturalized.
   --Littr['e].
   [1913 Webster]

   Droit d'aubaine, the right, formerly possessed by the king
      of France, to all the personal property of which an alien
      died possessed. It was abolished in 1819. --Bouvier.
      [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

AUBAINE, French law. When a foreigner died in France, the crown by virtue of
a right called droit d'aubaine, formerly claimed all the personal property
such foreigner had in France at the time of his death. This barbarous law
was swept away by the French revolution of 1789. Vide Albinatus Jus. 1
Malleville's Analyse de la Discussion du Code Civil, pp. 26, 28 1 Toullier,
236, n. 265.