http://en.wikipedia.org/wiki/Indigenous_peoples
International organisations[edit]
International Labour Organisation[edit]
The International Labour Organisation (Convention No. 169, concerning the rights of Indigenous and Tribal Peoples, 1989) in Article 1 contains a statement of coverage rather than a definition, indicating that the Convention applies to:


Miao girls in China
a) tribal peoples in independent countries whose social, cultural and economic conditions distinguish them from other sections of the national community and whose status is regulated wholly or partially by their own customs or traditions or by special laws or regulations;
b) peoples in independent countries who are regarded as indigenous on account of their descent from the populations that inhabited the country, or a geographical region where the country belongs, at the time of conquest or colonization or the establishment of present state boundaries and who irrespective of their legal status, retain some or all of their own social, economic, cultural and political institutions.

a me sembra che più che appartenenza o ceppo in senso etnico, sia più un discorso di "legal status"