They struck at the heart of Parisians’ Paris, diverse Paris, working class and modest bourgeois Paris, where I spent all my childhood and where my family and many of my friends live today.

They struck on a Friday evening, on a particularly mild November night when cafe terraces are still full of families. They struck during a friendly match between France and Germany at the Stade de France. They were ready to die, but only after they had killed as many people as they possibly could, armed to the teeth with weapons of war.

Since January, and the Charlie Hebdo and kosher supermarket massacre, we had seen a “new normal” settling in. We had got used to French armed forces guarding sensitive places, such as Jewish schools but also newspaper offices, we had got used to learning of artists, writers and intellectuals getting round-the-clock police protection, and to announcements telling us of thwarted attacks, here and there, notably against Catholic churches.

We had, in June, recoiled with horror after the first beheading on our soil of a compatriot, near Grenoble, the same day of Tunis’ Sousse Museum attack which left 22 people dead, mainly Europeans. And we had all wondered when, and not if, another attack would take place in our streets. We didn’t think it would come so soon though, or on such terrifying scale.

We had, in fact, not fathomed the scope of their potential action, nor had we fully measured the depth of their hatred. Friday 13 November will remain a marker of both their logistic capability, and of their loathing of democracy and civilisation. Who are they? Their modus operandi, among other things, their will to die and the reports that there were two suicide bombers who blew themselves up outside the Stade de France, leaves little doubt as to the nature of a terror we have come to live with: radical Islam.

France and its capital city seem to have been a particular focus of their abomination. Other European cities have been hit – Madrid, London and Brussels, for instance. But the viciousness those terrorists reserve for France is notable. For obvious reasons: France and Paris are the cradle of the Enlightenment, the birthplace of secularism and the separation between the State and the Church, a beacon of freedom of thought, scepticism and powerful satire. It is also an active player in fighting Islamists in the world, for example in Mali.

Many people will ask questions about failures in intelligence gathering and sharing, about prevention of such acts and they will be right. However, when the danger is so diffuse, no democracy that values freedom of speech and movement is completely safe.

For 35 years now, French governments, one after the other, have weakened the foundation of the République by allowing the rise of communitarianism. The extreme right is increasing its electoral hold, and so is antisemitism among young French Muslims.

I am not optimistic. At best, it will probably take a generation, perhaps two, to weave back together the fabric of society that has been shred to pieces on Friday night. What France needs is lucidity and courage. At worst? I don’t want to think about it.

• This article was amended on 14 November 2015. The original said a deadly attack in Tunis in June was at the Bardo Museum. This has been corrected.