No one who was in Paris on 7 January 2015 will ever forget the fear and horror that coursed through the entire city that day. This was the date of the massacre at the offices of the satirical magazine Charlie Hebdo, when, during an editorial meeting, twelve artists, editors and journalists were gunned down by two Islamist fanatics because they had ‘insulted’ the Prophet Muhammad. Eleven others were injured. I recall seeing the first grainy and disjointed images around midday on television in a cafe on the rue de Grenelle. The cafe was silent; these were scenes from a warzone, but they were happening no more than a mile away. One man spoke: ‘This is an act of war!’ No one disagreed.

Amid the dead bodies scattered across the office was the prone figure of Philippe Lançon, author and contributor to the magazine, still alive but only just. He was seriously injured, blood pouring from his arms and face, but at this stage he was too numb with shock to be aware of his wounds. He had to pretend to be dead as the Islamists prowled the room, intent on finishing off any of the survivors. Lançon dared not move but could not stop himself from opening his eyes for a few seconds to glimpse what his would-be killers looked like. Fortunately for him, their eyes did not meet.

Disturbance is a compelling and moving book. Only one chapter, however, is devoted to those terrifying minutes when Lançon’s life was in the hands of the Islamists. His account is detailed and precise; everything seems to be happening in slow motion. There is a chilling moment as he describes a gun hovering over him as its holder tries to make up his mind as to whether Lançon is dead or alive. Later, on an operating table, Lançon is still able to taste the buttery flavour of the last biscuit he ate before the carnage.

The greater part of the book documents the long aftermath of the massacre and the attempted journey back to a normality that no longer exists for Lançon. This is the ‘disturbance’ of the title, a year in which his life is dominated by medical and psychiatric treatment. ‘Disturbance’ is a good word to describe this rupture in Lançon’s life. But so is the French word lambeau, which was the original title of the book. It means a ‘shred’ or ‘scrap’, and in medical language refers to a useless flap of skin that refuses to heal after a cut or wound. This is now Lançon’s life.

There is no room here, however, for self-pity. Lançon spends long periods in hospital under armed guard but at least feels safe. He has to learn how to speak and eat again and to perform the most basic human functions, and is aware that the lower part of his face has been smashed into pieces. He compares himself to the First World War veterans with ‘broken faces’ who were treated in the same military hospital, Les Invalides, that he finds himself in. He is scared when he leaves this sanctuary – not just of the young Arab men he stands next to on a bus, but in a larger, more metaphysical sense: how to pick up the ‘scraps’ of his former life, which now seems distant and alien to him?

The way out of this for Lançon is art, literature and especially music. He was and is a cultural critic, not just for Charlie Hebdo but also for Libération and other journals. But now his books, pictures and favourite music take on a new life: they are not just cultural objects to be assessed and analysed but real, living companions in his life, as alive as the many friends and family who populate the book and who must also accommodate themselves to the new reality of Lançon’s condition.

Ultimately, this is a book about dignity. It begins with a savage and cruel inhumanity, but is really about rediscovering what humanity means and how human beings can withstand evil. For this reason, Disturbance is above all a monument to courage.

It is to Lançon’s credit that there is very little about politics in the book. This is all the more impressive given that shortly after the Charlie Hebdo murders, sickening but inevitable hand-wringing began among many on the Left – those who saw Charlie Hebdo as an outdated and reactionary magazine that indulged in Muslim-baiting as part of a generalised Islamophobia in France. The implication was that Charlie Hebdo somehow ‘had it coming’. Similar accusations have been levelled at Michel Houellebecq, whose book Soumission, which imagines France as an Islamic state, was coincidentally published on the same day as the massacre. Houellebecq is a ghostly presence in this book and the imminent publication of Soumission is part of the background to the events of 7 January.

The year 2015 was a terrible one in France. On 13 November, Islamists murdered scores of people at the Bataclan and elsewhere in Paris. The great merit of this book, however, is that it is not mere reportage or political journalism but a real work of literature: a journey into individual suffering. As such, it will long outlive the demented and bloodthirsty fools who tried to kill Lançon.