[3] Since 2002, Onana has published several books about the African Great Lakes region and the tragedies that have affected the four nations that border it: Burundi, the Democratic Republic of the Congo, Uganda, and Rwanda, with particular emphasis on the 1994 Rwandan genocide.

[12] In an article for the Fondation Jean-Jaurès think tank, academic Serge Dupuis calls the book an "investigation conducted exclusively to exonerate", very poorly supported by sources, and whose objective is "the pillorying of the RPF" (Rwandan Patriotic Front).

[14][15] In 2019, the International League Against Racism and Anti-Semitism filed a complaint against Onana for contesting crimes against humanity during a television interview about his book Rwanda, la vérité sur l'opération Turquoise.

[20] On 9 December 2024, Onana and his publishing director, Damien Serieyx, were found guilty by a Paris court of denying and downplaying the Rwandan genocide.

[23] He has written on the role and actions of African soldiers during the Second World War,[24][25] on René Maran,[26] on Josephine Baker and her involvement in counter-espionage on behalf of Charles de Gaulle from 1940,[27] on the involvement of the charitable organization Zoé's Ark in the 2007 kidnapping of 103 minors in Chad (co-written with the Chadian politician Ngarlejy Yorongar),[28] on the downfall of the former Ivorian president Laurent Gbagbo,[29] on the diplomatic relations between France, Israel, and the PLO during the tenure of former French president François Mitterrand,[30] and on Jean-Bédel Bokassa.