"The assassin is still out there," reads the headline over a picture of a bearded man -- representing God -- in bloodied robes and with a rifle slung over his shoulder in a special issue of the publication.
It's not the Prophet Mohammed this time, but "the God of all those who have faith," Sourisseau (who goes by the name Riss) told CNN's "Amanpour" program
"To us, it's the very idea of God that may have killed our friends a year ago. So we wanted to widen our vision of things. Faith is not always peaceful. Maybe we should learn to live with a little less of God."
The cover drew criticism from the Vatican's newspaper, L'Osservatore Romano, this week.
"Behind the deceitful flag of an uncompromising secularism, the French magazine once again forgets what religious leaders of different beliefs have been repeating for a long time: to reject violence in the name of religion," the newspaper wrote.
Might draw Mohammed again
But Riss, who survived the attack, said his magazine refused to censor itself.
"The French law allows for a lot of freedom. In the end, that's what counts: that the law prevails to protect us. After that, one has to have the courage to seize that right and put it to use. We can't sink into self-censorship," he argued.
"Maybe one day again we will draw Mohammed, as a matter of principle."
Charlie Hebdo is well-known for its satirical take on religion, politics and other topics.
The gunmen responsible for last year's massacre were apparently outraged by its depiction of the Prophet in cartoons, and the magazine's staff now live under constant threat of attack and have 24-hour police protection.
"We always have to be careful," Riss said. "We work with that idea in the back of our mind -- that maybe something someday may happen again."
'We had to rebuild ourselves'
But in an interview with CNN Correspondent Jim Bittermann to mark the one-year anniversary of the attack, he said the attacks on Paris two months ago showed it wasn't just cartoonists that were vulnerable.
"Maybe we had to wait until November 13 so that everyone could realize that such attacks could hit everyone, and not only cartoonists," he said.
"This past year has been very difficult," he reflected. "We had to rebuild the newspaper, we had to rebuild ourselves, confront our pains ... [But] we always manage to find the urge to laugh because we have the will to live. To laugh is like going to a restaurant, it's like going to a bistro for drinks. It's a pleasure that one has to continue to have. We don't have less of an urge to laugh."
Does he have any regrets?
"We don't ask ourselves, 'was it worth doing'? It's as if we were to say: 'Is it worth living, laughing, having fun?' If that were the case, you wouldn't do anything! So we didn't ask ourselves a question like that. For us, it seems obvious that in a country such as France, a secular country, we had the right to draw whatever we wanted."