Michel Houellebecq’s controversial new novel Soumission, in which France is governed by the “Muslim Fraternity” party, has shot to the top of the country’s bestseller lists with a first-week sale of more than 100,000 copies.

Published on 7 January – the day masked gunmen broke into the offices of the magazine Charlie Hebdo, killing 12 – Soumission (Submission) sold 120,000 copies in just five days last week, according to French trade magazine Livres Hebdo, putting it at the top of France’s book charts. There are 220,000 copies of the novel in print, according to Livres Hebdo, with the Bookseller also reporting “huge demand” for books of Charlie Hebdo cartoons and titles by the magazine’s cartoonists.

Narrated by a middle-aged academic, Soumission sees Houellebecq imagine France in 2022, where Front National leader Marine Le Pen is beaten by the leader of France’s new Islamic party, Mohammed Ben Abbes. Once Abbes is president, women go veiled in the street, and schools adopt an Islamic curriculum.

The work’s themes have been described as controversial – “France is not Houellebecq. It’s not intolerance, hatred and fear,” French prime minister Manuel Valls, told reporters – and Houellebecq’s publisher in France was placed under police protection in the wake of the attacks on Charlie Hebdo, with the novelist stopping promotion of the new book.

A caricature of Houellebecq featured on the cover of last week’s issue of Charlie Hebdo, published before Wednesday’s attack; it’s “not bad”, the novelist told an interviewer on Le Grand Journal this week, adding “Cabu [the late cartoonist] often did me – he was often funny”.

“Yes, yes,” a visibly shaken, tearful Houellebecq said when asked if he, too, is Charlie. “It’s the first time in my life that someone I love has been assassinated,” he said, referring to his friend Bernard Maris, who was killed in the attack. Houellebecq went on to insist that “there are no limits to freedom of expression, zero limits”, and that “freedom is often provocative. Freedom is not possible without a dose of provocation, maybe.”

Houellebecq has long been a lightning rod for controversy, appearing in court in 2002 for calling Islam “the stupidest religion”.

Asked about the remarks earlier this week, Houellebecq said he had changed his mind through reading the Qu’ran. “Perhaps I hadn’t read it with enough care,” he said. “Now I think that a reasonably honest interpretation of the Qu’ran does not end up with jihadism. It would require a very dishonest interpretation to arrive at jihadism.”

The novel is “not Islamophobic”, he added. “Even an inattentive reading would not see it as that,” he said.

A review in the Guardian agreed, arguing that while “some in France have already complained that the novel fans right-wing fears of the Muslim population … that is to miss Houellebecq’s deeply mischievous point. Islamists and anti-immigration demagogues, the novel gleefully points out, really ought to be on the same side, because they share a suspicion of pluralist liberalism and a desire to return to ‘traditional’ or pre-feminist values, where a woman submits to her husband – just as ‘Islam’ means that a Muslim submits to God.”

According to the Bookseller, Houellebecq will read from the novel at an event in Germany next week, where Soumission is due to be released as Unterwerfung, with an initial print run of 100,000 copies.