For France, it was the dawning of an annus horribilisA Latin phrase meaning "horrible year," made famous by Queen Elizabeth II in the 1990s. .

On 7 January 2015, brothers Cherif and Said Kouachi stormed into the Paris office of the satirical magazine Charlie Hebdo and opened fire. They left 12 people killed and 11 wounded.

The assault was sparked by the publication of cartoons depicting the Prophet Muhammad, founder of Islam. In Muslim doctrine, any depiction of Muhammad is blasphemySpeaking with contempt or disrespect about a religious deity or sacred person. Blasphemy laws were abolished in the UK in 2008. . For the Islamist Kouachis, Charlie Hebdo's images constituted an attack on their faith.

The tragedy soon became a flashpoint in a global debate on freedom of speechThe right to say, write and communicate thoughts and ideas without fear of censorship or reprisal.. Around six million people tweeted "Je suis Charlie", supporting the magazine's ability to publish without constraint. Others responded with "Je ne suis pas Charlie", signalling unease with the provocative cartoons.

This week, to mark the trial of 14 individuals suspected of planning the attack, Charlie Hebdo has reprinted the pictures. With them, it has reignited the debate. Should we be able to say - and publish - whatever we like?

Free speech is a sacrosanct pillar of Western democracies. In 1948, it was enshrined by the Universal Declaration of Human RightsOrganised by the United Nations in 1948, this document enshrines the rights and freedoms of all human beings. Although not legally binding, it provides the foundations of human rights laws in many countries.. It is because of free speech, its defenders argue, that we can criticise, challenge and expose the crimes and corruption of those in power.

By stopping the governments from controlling all information that circulates, free speech allows us to form our own opinions - even when they might clash with those of others. For some, this extends being allowed to mock everything, including religious beliefs. "There is in France", says Emmanuel MacronThe current president of France, nicknamed "Jupiter" after the chief of the Roman deities for his top-down manner of governance., "a freedom to blaspheme, which is linked to freedom of conscience."

Others would claim that we should exercise our freedoms with discretion. The Victorian philosopher John Stuart Mill formulated the harm principle, arguing that we should not act freely when we might hurt others. Regardless of their motivation, if republishing such scurrilousInsulting, scandalous language. According to the 18th-century Dictionary of Samuel Johnson, "using such language as only the licence of a buffoon can warrant". cartoons could cause harm - whether by insulting Muslim people, instilling prejudice or, even, as happened in 2015, inciting violence - they should remain shelved.

Critics could also point out the hypocrisy of societies that promote some forms of expression but punish others. In France, you can be fined for booing the national anthem, raising the question: why can a figure sacred to Muslims face mockery but not something valued by another demographic? An important rule of free speech is that we show equal respect to all groups, even those we might disagree with.

Oui, some would say. The right to speak freely is what sets democracies apart from repressive dictatorships. A plurality of opinions helps promote fruitful debate. And whatever one thinks of the cartoons, the freedom of the press to publish them should be defended to the hilt as a sign of a fair society. If you're offended, c'est la vie - you can exercise your own free speech and launch a critique.

Non, argue others - and not just because their previous appearance led to tragedy. Free speech is important, but we also have a duty to remain silent when speaking may promote hate. There is a difference between stoking debate and fuelling division. Whether or not Charlie Hebdo intends to encourage prejudice against Muslims, the possibility that it might is reason enough to pulp it.

Annus horribilis - A Latin phrase meaning "horrible year," made famous by Queen Elizabeth II in the 1990s.

Blasphemy - Speaking with contempt or disrespect about a religious deity or sacred person. Blasphemy laws were abolished in the UK in 2008. 

Freedom of speech - The right to say, write and communicate thoughts and ideas without fear of censorship or reprisal.

Universal Declaration of Human Rights - Organised by the United Nations in 1948, this document enshrines the rights and freedoms of all human beings. Although not legally binding, it provides the foundations of human rights laws in many countries.

Emmanuel Macron - The current president of France, nicknamed "Jupiter" after the chief of the Roman deities for his top-down manner of governance.

Scurrilous - Insulting, scandalous language. According to the 18th-century Dictionary of Samuel Johnson, "using such language as only the licence of a buffoon can warrant".