The ILO Core Conventions [page 31]:

The eight ILO core conventions provide a globally recognised framework for what constitutes a decent working life. The conventions are of key importance for the UN Guiding Principles on Business and Human Rights, the UN Global Compact and the OECD Guidelines for Multinational Enterprises. They include the following areas: (…) The elimination of forced or compulsory labour (Convention No. 29 on Forced Labour, and Convention No. 105 on the Abolition of Forced Labour).