The novel is set over a twenty-four hour period in Fort-Jacul, a Central African country recently independent from French rule. It begins with twenty-six-year-old French UNESCO employee Avit landing at the airport in Fort-Jacul, and ends with him leaving it. He has spent two years recovering from his very young wife Laurence just leaving him and taking off with another man, although he finds shortly after arriving in Fort-Jacul that Laurence is in Fort-Jacul too and now living with Patrice Doumbé, the country's minister of health.
And on landing, Avit is sent to see Modimbo, the Ministre de l'Information, who in no uncertain terms tells him to go home, although he doesn't say why. It becomes quite clear that the reason is the blacks' prejudice against the whites, and this is seen throughout the book, from the killing of Doumbé whose relationship with Laurence causes anger among the population, through the increasingly violent and threatening atmosphere of the country, all the way to the thousands of black and white people following Laurence and Avit to the airport.
The book was faithfully adapted into a film whose screenplay was written by Conchon and the director Francis Girod in 1978. I'm unsure how such works would fair in a post-politically correct age though.