You can't call someone a nigger because there's an ugly history to the word, and that's why people take offence to it. People take offence to crude drawings of Mohammed because Islam forbids idoaltry. How in the world a caricature depicting Mohammed in a lewd pose is idoaltry is beyond any rational person, but whatever. In my opinion if anything, they should be celebrated as they are the exact opposite of idolatry, but I am evidently not a Muslim scholar.

To compare the Muhammad cartoons with using the word 'nigger' is really a stretch. France has had ...let's say 'trouble'... with Algeria in the past, and one could argue that there is an Algerian 'underclass' in French society, and thus Algerians are comparable to black people in the States, but this point is contestable. First of all Algerians were not slaves for hundreds of years, there was no Emmett Till equivalent (afaik), no lynchings, no KKK equivalent, and so forth - all as evidenced by the fact that there's no concept of making a word deadly taboo for a select group of society because it would be a throwback to such incidents. Second of all, Algerians are not the same thing as Muslims, so the whole concept of a historically disenfranchised Muslim underclass is sort of moot, even if there were strong arguments about Algerians being historically disenfranchised.

'Nigger' is an American word and is born of American culture. Beyond the fact that I don't think it's the same thing as the Muslim experience (in France or anywhere else, really), you cannot view the world through an American prism. French values are very different, going all the way back to Voltaire - who, coincidentally, was the lawyer defending the last convicted blasphemer in France. Think about that, that predates the revolution.

To paraphrase a French author, blasphemy is a national sport in France. Charlie Hebdo was a uniquely French magazine that promoted French values: their laïcité, their nigh on nihilism, their irreverence. The best example of this is the fact that Charlie Habdo spared nobody, and frequently made fun of extreme right-wing politician Marine Le Pen, as well as the Pope, comedian and arguably anti-semite Dieudonne, etc. In that respect, because the cartoons didn't treat Islam or Mohammed differently from any other part of French society or culture, you could even argue that they were an exercise in tolerance and inclusion. You are with us, you are part of Western society, you are part of France, you are now just as much a target as anybody else.