Parisians from across the city clogged the metro on their way to Place de la République for the enormous vigil that the world has now watched and echoed from New York to Zagreb. People were still reeling from the cold-blooded killings that resulted in the deaths of twelve people, including four of France’s most celebrated cartoonists, at the offices of the satirical weekly Charlie Hebdo.

One elderly woman standing alone and, almost in spite of herself, held a pen in the air. “I didn’t have time to make a sign,” she explained, “this seemed like the right thing to do.” Twenty minutes later, pens and pencils were raised all over the square. Various voices rang out from around the crowd before the simplest messages were adopted by most of the mourners: “liberté, expression !” “l’encre doit couler, pas le sang !” (ink must flow, not blood!). It was these simple messages, that made me realize the significance of Charlie Hebdo.

Charlie Hebdo isn’t everybody’s cup of tea. Beyond its mission to bring anything or anyone who takes themselves too seriously down a notch or two, it gave itself for objective to say the unspeakable, to shock and offend, in the most equitable, the most French way possible: everything has to be fair game – men and women, the rich and the poor; power, politics and religion alike – if not, the game is rigged.

It is part of a tradition of French satire that is as rich as it is long, and over the centuries, few have been spared. France’s royals, its priests, the Pope and public personalities from left to right have all found themselves on the business end of the caricaturist’s pencil. It is part and parcel of the Voltairian spirit of freedom of expression, famously distilled by his biographer in the phrase: “I disapprove of what you say, but I defend to the death your right to say it.”

Thinking about this as one of 35,000 people that gathered on the night of the attack, it struck me that although Charlie Hebdo was not the most widely read publication, its role patrolling and playing with the boundaries of the freedom of expression keeps the centre ground alive. Its cartoonists empower the mainstream media to remain open and imaginative, the press to remain spontaneous. Their work, on the margins, helps cultivate a larger space in the middle for France to consider, question and constantly re-imagine itself.

It is paradoxical that the jesters of Charlie Hebdo would be made martyrs of a free press, most notably because the idea of martyrdom has been a frequent subject of their satire. These journalists were French household names, their work instantly recognizable, their style held in affection. Paris here stands universally defiant, “not afraid,” in dignified repudiation of the violence visited upon their country by terrorism. It is mourning the loss of innocent lives, whatever the answer to questions of “how” and “why.” But beyond that, and perhaps unconsciously, France is making icons of their icon-slayers.

The massive manhunt for the two principle suspects has led to not one but two hostage-takings, keeping the country on edge in what was already the worst terrorist attack on French soil in over half a century. The amateur video footage that seems to have captured the suspects shouting, “We have avenged the Prophet Muhammad,” and “Allahu Akbar” (God is great) is now well-known. Charlie Hebdo, which satirizes the establishment in all its forms, has been attacked several times in recent years, including by firebomb in 2011 after it named the Prophet Muhammad as its Editor-in-Chief.

This was an attack shocking not only for its cold-blooded violence or as a human tragedy, but as one of the most brutal manifestations in Europe of tensions that many believe will mark a generation. Against a rising tide of anti-immigration politics and with the French and the British involved in efforts to stave off the Islamic State in Iraq and Syria, terrorist attacks in Europe are an increasing security concern.

But this layer of political context was far away from the vigil at Place de la République that took place six hours after the attack. I saw no one offering explanation, interpretation or conclusion – no would-be prophets or politicians – just men and women presenting themselves in solidarity and to grieve. The intrusion of meaningless violence in the city and, beyond that, against values they are proud to call French, had brought Parisians together in this space consecrated by the city to the people’s tradition of manifestations.