PARIS — There's a nice trompe l'oeil mural on rue Nicolas Appert here in the 11th arrondissement. I once stood in front of it for a little while on my lunch break, trying to make sense of the artist's visual tricks.

Today, making sense of what happened on that street feels impossible: Twelve people, among them some of France's best cartoonists, with plenty of visual and rhetorical tricks of their own, were gunned down at the offices of satirical weekly Charlie Hebdo. Just a three-minute walk from where I myself work with words and images to try to make our own, different kind of sense of the world.

I should confess from the start that I've never been a regular reader of Charlie Hebdo — hell, I don't even think I've ever bought it. All the same. Cabu, Charb, Tignous, Wolinski: Familiar names and faces, drawing styles that a bande dessinée lover like myself could instantly recognize and appreciate. And though I sometimes have found that Charlie Hebdo provokes just for provocation's sake, never has it been clearer that their right to do so is sacrosanct.

In their own idiosyncratic and immediate way, cartoonists can be considered the front line of free expression in France, le pays des Lumières. Today we see just how much was at stake, and at risk, from where they stood.

The more straightforward media I work for, Worldcrunch — though produced in English — is based in Paris not just by chance. The French capital's cultural, ethnic and political melange, and its distance from the traditional Anglo-American viewpoints, makes it the perfect place to cover the world.

So this attack hits home. Not only because of its geographic proximity to our offices, but because it crosses a new line in the way that people are increasingly targeted for their ideas and for their work delivering information. When American war correspondent James Foley was killed and decapitated in Syria in August, it was horrible of course, yet somehow remote to those of us working in supposedly safer parts of the news business.

We don't know yet who carried out this morning's shooting. Regardless, it is scary to think that the ramifications of intolerance are such that they can wreak havoc in a quiet, nondescript Parisian street, and that people can be killed for making drawings on paper.

I worry about the devastating effect on some people's opinion on Islam, tainted by a few extremists, and what it will mean for that singular way we've always managed to live together in Paris, whether you come from East Asia, East Africa ... or like me, a small town in eastern France.

I will go to the demonstration in Place de la République tonight. Not because caricaturing Muhammad makes me laugh. It doesn't. But I want to stand alongside people who also think that others have the right to do so. Also, I have always found it strangely comforting the way demonstrations can pack thousands of strangers close together in peace — and right now I could use just that kind of comfort.