A comparison between the Charlie Hebdo attack in January and Friday’s mass bombings is very instructive.
Both took place in Paris. But there the resemblance ends.
January’s attack was directed at the offices of a paper that had provoked Muslims everywhere by its cartoons on the Prophet. That attacked is ascribed to the Al Qaeda group.
Friday’s attack was by ISIS, the new terror group.
For most of last year and much of this, IS's focus has been on taking and holding territory in the Middle East. For its leaders in Raqqa and Mosul, that is still the priority.
In June, IS claimed a gun attack at a Tunisian beach resort in Sousse that killed 38 tourists, 30 of them British.
In October Turkey blamed a suicide attack killing 102 people in Ankara on IS.
Later that month, IS's Sinai affiliate claimed to have brought down a Russian airliner, killing all 224 people on board.
On 12 November, IS claimed the bomb attack on the Hezbollah stronghold in south Beirut that left 44 people dead.
And then came Paris, with at least 120 dead and over 300 injured.
Compared to Al Qaeda, Isis’s attacks are indiscriminate, almost random. They shoot to kill whoever happens to be there, Muslims even.
On Friday, they attempted to set off suicide bombs in the Stade de France, among the crowds watching the France – Germany game. It was only because they were foiled, that they did not manage that. The carnage would have had a far wider, more sinister world-wide echo, comparable to when we saw the first and then the second plane crash into the Twin Towers.
Although not necessarily difficult to execute, these attacks still took planning, preparation, training, sourcing of weapons and explosives, reconnaissance of the target and the careful recruitment of so-called "martyrs" - fanatical young men prepared to carry them out in the full knowledge they will probably die doing so.
This is far more reminiscent of al-Qaeda's modus operandi in the early 2000s, going for big publicity, high-casualty attacks that make headlines around the world.
There is now a huge international search for accomplices and perhaps even gunmen who have escaped. Thanks to the security services, and also thanks to modern means of sifting through evidence, the whole supporting network may be discovered.
It will of course be too late for the dead victims and their families, marked for life by the tragedy.
There will now be the many public manifestations of solidarity (maybe not in the way the world reacted at the Charlie Hebdo massacre), minutes of silence, people donning the French colours on Facebook, the lot. Such manifestations have become a ritual.
A more predictable consequence will be the hardening of Europe against migrants, the strengthening of the xenophobic parties all across Europe and the dismantling of Schengen and the ‘Open Door’ policy practices with regards to the Syrian refugees.
This will not be enough. Many are already calling for an intensification of the fight against ISIS not just in Syria but also in Libya and wherever the instability of the region is allowing ISIS a free rein.
But Friday’s wave of terror underlined how easy it is for terrorists to cause mayhem on a vast scale. The targets were not the heavily policed venues but low-key - a fast food outlet, a concert outlet, a Cambodian restaurant - none are venues frequented by the rich and famous. All congregated people of different faiths, political views, and races. And a Paris arrondissement that is inhabited by the ordinary, working class, people, not those where the rich live.
The stark choice is thus between turning every city, every country, into a fortress or facing the risk realistically, while increasing the firepower to find and destroy ISIS and its leaders everywhere. Even so, the nature of this kind of terrorism is that it has become quite easy to recruit easily impressionable youngsters who fall out of the modern Western civilised world and turn them into fanatical terrorists afraid of no one.