22 January 1992
Nelson Mandela, leader of the African National Congress (ANC) and President F.W. de Klerk were awarded the Unesco Houphouet-Boigny Peace Prize for 1991. They received the prize on 3 February in Paris, France.
References

Kalley, J.A.; Schoeman, E. & Andor, L.E. (eds)(1999). Southern African Political History: a chronology of key political events from independence to mid-1997, Westport: Greenwood.)|GCIS/ANC, Profile Information: Mandela, from Government Communications, [online], Available at apps.gcis.gov.za [Accessed: 10 January 2014]