This is a case of a novel of ideas with the best (or worst) possible timing. The very day it was published in French was the day of the Charlie Hebdo shootings; a few short weeks after the English translation came out, Paris was attacked again. 
 Our protagonist, whose name I've already forgotten, is a professor of 19th century literature and an gormless slob who eats microwave food and hires prostitutes to lick his balls. He, like many Houellebecq protagonists, moves through life with a depressed indifference. That is, until the 2022 elections and the fictitious Muslim Brotherhood Party edges out the Front National. 
 He is the 'main character', but his life is shaped by Muhammad Ben Abbes, who is the Nietzschean 'Ubermensch' to our protagonists' 'Last Man'. He is charismatic, sharply intelligent, and the sort of man who makes other men surrender to him willingly. In this curious way, he is the strong leadership which the far right craves, with the exception that he leads a Muslim revitalization of Europe instead of a Christian one. Unemployment and crime plummet, political squabbles perish, Europe rises to challenge and equal the United States, and the nation is a unified, organic whole. With the exception of the new underclass, women. But our protagonist doesn't really care about them. 
 Houellebecq's dystopia is apparently not the one where the fictitious Muslim Brotherhood takes over; it's the one with an anemic market liberalism which makes any takeover possible, or preferable. You almost get the sense that Houellebecq would approve of any new regime (even if you consider the Margaret Atwood-esque fate of all the women). His deep pessimism parallels his professional subject, Huysmans - a move from decadent overindulgence to the comfort of belief. Whether that belief is sincerely held is another matter. 
 Houllebecq's study does not cover sharia law or fundamentalism or any of the caricatures of Muslims which haunt the media or political debate. It is a study of collaboration horizontale with a new regime. This is the sort of person who would willingly abandon their old France, leaving behind 'nothing to mourn' for the prospect of material gain. This is apparently the sort of person who would favor any extremism, any man who would covet arranged marriages and obedient slave-wives because any social movement for women is threatening. They are not so poor that they'd be on the edge of survival, but just well off enough to have time to be frustrated and miserable. 
 An interesting idea, but I wonder if people will discuss it for all the wrong reasons.