The narrator is only known by his nickname Fessologue, after the neologism fessologie, the study of (women's) 'faces B', or 'B sides'. The expression 'B sides' comes from the flipsides of vinyl discs which used to swing, like women's backsides, and Fessologue is an expert on those, always visually investigating them. He says 'The science of backsides has existed since the world began, when Adam and Eve turned their backs on the Lord.'
Fessologue called his former partner (by whom he has a child) Couleur d'origine: she has her origins in the Congo too, although she was born in France, but retains her 'colour of origin': colour is significant in the book, as well as buttocks, such as the narrator's implied criticism of blacks using whitening products. But Couleur d'origine walks out on him with their child, into the life of l'Hybide, a tam-tam player.
Books are important in this novel too, and many of them are mentioned, such as some by Louis-Philippe, who's from Haiti, who Fessologue meets at a book-signing session, and who is actually Louis-Philippe Dalembert, although his surname is never given here. Fessologue starts reading in earnest, and is now writing too, a book called 'Black Bazar'. He's bought a typewriter and writes everywhere he goes about his life, the things he does, the people he meets, the conversations he has, his Arab grocer opposite, Hippocrate the tenant from Martinique who thinks he's a concierge and is always watching him and complaining about cooking smells, etc.
And along comes Sarah, a Franco-Belgian girl with fine buttocks, who introduces Fessologue to Belgian culture, such as the Goncourt-winning Béatrix Beck's Léon Morin, prêtre (1952). She reads Fessologue's novel and says: 'I was waiting for you to finally finish your book to tell you that I'd like you to come and live with me.'
My other posts on Alain Mabanckou:
Alain Mabanckou: Verre Cassé | Broken Glass
Alain Mabanckou: Lettre à Jimmy | Letter to Jimmy