Not even the rudest insults can justify terror attack on French magazine Charlie Hebdo

France is no stranger to terror attacks, but the one carried out on the satirical weekly magazine Charlie Hebdo has jolted the nation like none since the second world war. The shock is understandable: the men who brutally gunned down 10 journalists and two policemen were also targeting democracy, freedom of expression and the press, core values in French society. Those concerns have reverberated around the world to communities that strive to uphold the highest standards. Fiercely defending those freedoms is the best response to such violence and blatant disregard for cherished beliefs.

The two men who went to the magazine's Paris office with assault rifles had no such values. They wanted revenge against its cartoonists and journalists for poking fun at their religion, Islam, and its prophet, Mohammed. The attack was carefully planned; a meeting room was entered, the shots fired, people who got in the way, policemen among them, were gunned down in cold blood, and an escape was made with the help of a third man, a driver. It was the third case in three years in France of radical Muslims going on a shooting spree, yet the country's intelligence services were unaware of the plot.

That has to be a wake-up call for France and the world. The US-led war on terror decimated the extremist group al-Qaeda, but others have emerged from the civil unrest in the Middle East and Africa. Whether the Paris attackers were members of any of them is not known, but one had a criminal record and links to Islamic fighters in Iraq. Governments have to better monitor citizens with radical views and more stridently deal with those involved or connected with overseas insurgencies.

As importantly, values have to be protected. Charlie Hebdo revelled in testing the limits of press freedom and ridiculed anyone and everything. Its cartoonists and journalists were unafraid and unbiased in aiming their satirical barbs, even when faced with violence and threats. A firebombing of their office in 2011 over an issue dedicated to jokes about the prophet and his followers did not deter them.

The cartoons that prompted the attack are offensive to some people, but not others. Most media organisations have refused to reprint them on the basis that there are limits to freedom of expression. No matter how detestable they may seem, though, that is not a justification for violence. Every nation, society and culture has its values and they have to be respected. The attack can only be condemned in the strongest terms.