The rioting occurred when members of the Alliance des Bakongo (ABAKO) political party were not allowed to assemble for a protest and colonial authorities reacted harshly.
While there were no universal criteria for determining évolué status, it was generally accepted that one would have "a good knowledge of French, adhere to Christianity, and have some form of post-primary education.
[7] This became increasingly difficult as Congolese nationalism became more popular, so in July 1958 the Belgian government established a study group to consider new reforms in the colony.
[8] On 28 December 1958, Lumumba organized a major MNC rally in Léopoldville where he reported on his attendance of the All-African Peoples' Conference in Accra, Ghana earlier that month.
Noting the success of the rally, Kasa-Vubu decided to organize his own event one week later, on Sunday January 4, 1959[6] to discuss African nationalism.
[6] At the time press accounts estimated that 35,000 Africans were involved in the violence, which quickly spread as the rioters attempted to enter the European section of the capital.
[6] Order was restored with the use of African police officers in the employ of the colonial government and with armored cars under the direction of General Émile Janssens.
[12][13] Colonial authorities arrested as many as 300 Congolese, including Kasa-Vubu, who would later become the newly independent Congo's first president, Simon Mzeza[14] and ABAKO vice-president Daniel Kanza and charged them with inciting the riot.
It also concluded that external political events, such as France's decision to grant self-governance to the neighboring French Congo, to be a contributing factor, and criticized the colonial administration's response to the riot.
On 13 January the administration went forward with its scheduled announcement of reforms, including new local elections in December, the institution of a new civil service statue that made no racial distinctions, and the appointment of more Africans to advisory bodies.