Article 8 International Covenant on Civil and Political Rights (ICCPR)

1. No one shall be held in slavery; slavery and the slave-trade in all their forms shall be prohibited.

2. No one shall be held in servitude.

3.

(a) No one shall be required to perform forced or compulsory labour;

(b) Paragraph 3 (a) shall not be held to preclude, in countries where imprisonment with hard labour may be imposed as a punishment for a crime, the performance of hard labour in pursuance of a sentence to such punishment by a competent court;

(c) For the purpose of this paragraph the term “forced or compulsory labour” shall not include:

(i) Any work or service, not referred to in subparagraph (b), normally required of a person who is under detention in consequence of a lawful order of a court, or of a person during conditional release from such detention;

(ii) Any service of a military character and, in countries where conscientious objection is recognized, any national service required by law of conscientious objectors;

(iii) Any service exacted in cases of emergency or calamity threatening the life or well-being of the community;

(iv) Any work or service which forms part of normal civil obligations.

See also: Article 7 ICCPR