France has been less obviously affected by militancy than many European nations, and the route followed by the Toulouse suspect appears exceptional
Over the last decade, despite the ongoing controversy centred on the veil and similar issues, France has been less obviously affected by the violence of the 9/11 wars and the broad phenomenon of contemporary Sunni Muslim Islamist militancy than many other European nations.
Unlike the UK and Spain, there have been no mass casualty attacks. There has been no high-profile assassination such as that of the film-maker Theo van Gogh in the Netherlands.
France was hit by the blowback from the civil war in Algeria in the 1990s, suffered from its own particular brand of "gangster jihad" prior to 2001. A handful of Frenchmen were present in Afghanistan, with at least one dying in the fighting at Tora Bora.
There was also a well-developed pipeline that channelled a couple of hundred volunteers to Iraq between 2003 and 2006. There have been instances of young Frenchmen travelling to south-west Asia since, but there has been no equivalent of the flow of young British Pakistanis to Pakistan's tribal regions. One or two did make the trip, but none returned to execute attacks such as 7/7.
This makes the route apparently followed by Mohammed Merah – and we are still waiting for full confirmation that he did indeed spend time in the region and details of what he did there – all the more exceptional.
One reason for this, beyond obvious logistical issues such as language, is the undoubted expertise of the French security services which, in part due to the knowledge gained in the 1990s, understood the challenge of diffuse, networked and ideologically-driven Islamist extremism much faster than their Anglo-Saxon counterparts.
Another is the origins of the very large French Muslim community. In contrast with the poor, illiterate and deeply conservative communities in Pakistan to which many in the UK trace their origins, many French Muslims have roots in the relatively moderate, relatively prosperous and much better educated Maghreb.
With trends in countries of origin still strongly influencing immigrant origin populations, this is significant. French opposition to the war in Iraq also helped.
The role of French secularism is much less clear. Polls in France over recent years have shown two apparently contradictory trends. Young French second or third generation "Muslims" are increasingly integrated in terms of drinking alcohol or inter-marriage, but are also more likely to attend mosque or wear the veil.
Economic and cultural marginalisation remain significant. Though no official statistics exist, the number of Muslims in prisons, identified often by their refusal to eat non-halal prison meat, is extremely high.
One thing that is typical about the profile of Merah is his background of relative poverty, petty crime and, according to neighbours, lack of obvious signs of radicalism.
Security services in France worry that this latter population is vulnerable to recruitment by conservative "Salafi" organisations. Recent years may not have seen a surge of Islamist extremist violence – though a relatively high level of antisemitic attacks by mainly young Muslims has been recorded – but have seen ultra-conservative, if nominally pacifist, groups such as the Jamaat Tabligh make significant inroads.
A steady flow of young French Muslims to Gulf states such as Saudi Arabia and Kuwait to study in religious schools where a harsh and intolerant version of Islam is taught is an equally major concern.
Overall, however, the French security services remain sanguine. They support expert analysis that the riots of late 2005 were not a "European intifada", as described by rightwing commentators in the UK and the US, but a classic case of urban violence.
They argue that the continuing absence of a serious 7/7-style conspiracy since is testament to the overwhelming moderation of the Muslim community in France. They also say that, though France's banning of the burqa is an emotive issue, any anger does not translate directly into violence.
British security officials say their biggest current concern in continental Europe is Germany, where a very substantial Muslim population appears to be more radicalised now than it was only a few years ago.
As more details emerge of the gunman and any associates, European intelligence services may have to revise their analyses. If it is indeed the case that the suspect "was followed for several years", as Claude Gueant, the French interior minister said, the reputation of the nation's security apparatus will be significantly tarnished.
Western security services are already concerned by "fast turnaround" volunteers slipping in and out of Pakistan very rapidly and thus escaping notice. If Merah did spend time in Afghanistan and had contact with groups close to al-Qaida or even the late Osama bin Laden's organisation, this will increase anxiety significantly.
Merah was reportedly picked up and went on to kill. What, the question will be, can be expected from those who have not been identified? Calm and informed debate – in France, certainly – will probably have to wait until after the forthcoming presidential elections.