UN General Assembly Resolution 194 (III), 11 December 1948 (and reaffirmed every year since):
Resolves that the refugees wishing to return to their homes and live at peace with their neighbors should be permitted to do so at the earliest practicable date, and that compensation should be paid for the property of those choosing not to return and for loss of or damage to property which, under principles of international law or in equity, should be made good by the Governments or authorities responsible.

Universal Declaration of Human Rights, (10 December 1948)
Everyone has the right to leave any country, including his own, and to return to his country.  (Article 13(2)).
 

International Convention on the Elimination of All Forms of Racial Discrimination, (21 December 1965)
“…State Parties undertake to prohibit and to eliminate racial discrimination on all its forms and to guarantee the right of everyone, without distinction as to race, color, or national or ethnic origin, to equality before the law, notably in the enjoyment of…the right to leave any country, including one’s own, and to return to one’s country.”  (Article 5(d)(ii)).

International Covenant on Civil and Political Rights, (23 March 1976)
 No one shall be arbitrarily deprived of the right to enter his own country.” (Article 12(4)).