I think Michel Houellebecq is a very good writer - sometimes superb - but I don't think this is a good novel. It doesn't really work.
He imagines France a few years on from now (2022) electing a (moderate) Islamic President one of whose (less moderate) priorities is to islamicise - with the help of Saudi Arabian funding - university education. The events of the novel unfold through the eyes of a jaundiced professor who is cast, first, as an Outsider à la Camus: there is an obvious nod to the opening page of L'Etranger at page 174. But he is cast, second, as a faux naïf who sits open mouthed (always nibbling at the canapés or the mezze) as others, more clued in politically, give him lessons in what is happening to France. These lessons take the form of set piece speeches, delivered by a secret policeman and a university rector to their audience of one. It is one of the drawbacks of a roman à thèse that you are forced into such desperate literary devices.
I should add that the narrator is also cast, third, as an academic expert on J K Huysmans, sufficiently distinguished to get the invitation to edit a Pléiade edition of his works. What Houellebecq writes about Huysmans is interesting and clearly knowledgeable; some university should probably give Houellebecq a doctorate for his thesis and overlook the novel.
Houellebecq can be an amusing writer when he wants to be but I am not sure - maybe my French isn't good enough - if he intends that we should be in fits of laughter as he brings his novel to a close. His narrator likes food and sex, preferably free but he will pay for both if necessary. He's a bit down on his luck when he is compulsorily retired from the new islamicised Sorbonne. But he is tempted back. He sees what is happening to those of his colleagues who have converted to Islam. They not only have the salaries, but new wives. The rector of the University has been given a 15 year old, very sexy, but also has an older wife who can cook, very well.
And so the narrator, after dutifully reading the little introduction to Islam provided, discreetly enquires - If I accept the invitation to return, for how many wives would I qualify? Well, there is no obligation to take all of them, but we could probably offer you three. That settles it and, to the delight of his colleagues, our Vicar of Bray returns to his university post.