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]

The Collaborative International Dictionary of English v.0.48:

Droit \Droit\ (droit), n. [F. See Direct.]
   A right; law in its aspect of the foundation of rights; also,
   in old law, the writ of right. -- Abbott.
   [1913 Webster]

   Droit d'aubaine. See under Aubaine.

   Droits of the Admiralty (Eng. Law), rights or perquisites
      of the Admiralty, arising from seizure of an enemy's ships
      in port on the breaking out of war, or those coming into
      port in ignorance of hostilities existing, or from such
      ships as are taken by noncommissioned captors; also, the
      proceeds of wrecks, and derelict property at sea. The
      droits of admiralty are now paid into the Exchequer for
      the public benefit.
      [1913 Webster]

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

DROIT D'AUBAINE, jus albinatus. This was a rule by which all the property of
a deceased foreigner, whether movable or immovable, was confiscated to the
use of the state, to the exclusion of his heirs, whether claiming ab
intestato, or under a will of the deceased. The word aubain signifies hospes
loci, peregrinus advena, a stranger. It is derived, according to some, from
alibi, elsewhere, natus, born, from which the word albinus is said to be
formed. Others, as Cujas, derive the word directly from advena, by which
word, aubains, or strangers, are designated in the capitularies of
Charlemagne. See Du Cange and Dictionaire de Trevoux.
     2. As the darkness of the middle ages wore away, and the light of
civilization appeared, thing barbarous and inhospitable usage was by degrees
discontinued, and is now nearly abolished in the civilized world. It
subsisted in France, however, in full force until 1791, and afterwards, in a
modified form, until 1819, when it was formally abolished by law. For the
gross abuses of this feudal exaction, see Dictionaire de l'Ancien Regime et
des abus feodaux. Aubain. See Albinatus jus.