He added: "It's normal. You cannot provoke. You cannot insult the faith of others. You cannot make fun of the faith of others."
Many people around the world have defended the right of Charlie Hebdo to publish inflammatory cartoons of the Prophet Mohamed in the wake of the massacre at its Paris offices and the following attack on a kosher supermarket, in which three gunmen killed 17 people in total.
But recently the Vatican and four prominent French imams issued a joint declaration that denounced the attacks but also urged the media to treat religions with respect.
Francis, who has urged Muslim leaders in particular to speak out against Islamic extremism, went a step further when asked by a French journalist about whether there were limits when freedom of expression meets freedom of religion.
Francis insisted that it was an "aberration" to kill in the name of God and said religion can never be used to justify violence.
But he said there was a limit to free speech when it concerned offending someone's religious beliefs.
In the wake of the Paris attacks, the Vatican has sought to downplay reports that it is a potential target for Islamic extremists, saying it is being vigilant but has received no specific threat.
Francis said he was concerned primarily for the faithful, and said he had spoken to Vatican security officials who are taking "prudent and secure measures."
- The Independent / AP