DiÃ¨ne holds a law degree from the University of Caen (France), a doctorate in public law from the University of Paris, a diploma in political science from the Institut d’Etudes Politiques in Paris, and an Honorary Degree of Doctor of Laws degree from the University of the West Indies (Cave Hill, Barbados)
Between 1972 and 1977 he served as Senegal’s deputy representative to UNESCO. In 1977, he joined the UNESCO secretariat, where he held several positions including Director of the Division of Inter-cultural Projects. He was appointed Special Rapporteur for racism-related topics by the United Nations Commission on Human Rights in August 2002, replacing Maurice Glele-Ahanhanzo of Benin and serving until July 2008 when he was succeeded by Githu Muigai (Kenya).
In 2011, he was appointed Independent Expert on the situation of human rights in CÃ´te d’Ivoire.