Yet even producing the paper and housing its staff have become a new kind of challenge.

This month, Charlie Hebdo moved into rented office space after squatting for more than six months in an improvised space carved out of the newsroom of Libération. The new address, in Paris’s working-class 13th Arrondissement, is not public. On top of its expensive new security system, the newspaper expects to spend an additional €500,000 a year on armed guards.

“All that, just to be able to work,” Mr. Portheault said.

Mr. Sourisseau, who is protected by a five-officer police retinue, bristles at the diversion of resources to security, but he said: “We cannot reasonably go back to functioning the way we used to. That would not be responsible.”

With the anniversary of the attacks approaching — and the expectation that many of those who took out a subscription this year may not renew — Charlie Hebdo anticipates that its readership could drop by at least one-third, to perhaps 200,000 in 2016. Last week, the newspaper introduced a revamped website, which offers a mix of free and paid content — including selected articles and cartoons in English — and it plans new mobile apps as well. A 34-page special issue is in the works for January.

Charlie Hebdo’s journalists are well aware that their particular brand of in-your-face humor will not always resonate with its newfound readers. Mr. Sourisseau shrugged at the recent social media storm provoked by one of his cartoons, which mocked Europe’s muddled response to the migrant crisis with an image inspired by a photo of a drowned Syrian boy.

“When you draw a cartoon, it’s like throwing a message in a bottle,” he said. “You never know how it’s going to be received.”

The whole point of satire, Mr. Sourisseau said, was to destabilize in order to enlighten people about often uncomfortable truths. Publications like Charlie Hebdo, he and his colleagues said, provide a necessary antidote to what they described as social-media-driven public discourse filled with sanitized images and commentary divorced from context.

“It’s worrying to hear people tell us, ‘You’re the only ones who can say such things,’ ” Mr. Sourisseau said. “We don’t want to be alone in seeing the world the way we do. It’s a bad sign if we become just a symbol of something that’s slowly fading away.”