Nice is known for its beaches and traditional architecture, but law enforcement and experts on terrorism say its suburbs are unhappier places that have recently become breeding grounds for Islamic militancy.
That appears to have reached a deadly crisis point with the attack on a Bastille Day holiday crowd
that left more than 80 people dead and others critically injured.
The incident follows previous extremist strikes in France
-- including November 2015's massacres in Paris and January 2015's attack focused on satirical magazine Charlie Hebdo -- that have plunged the country into a state of emergency.
In the aftermath of the latest killings, as questions are asked over whether the bloodshed could have been prevented, scrutiny will fall on what was known about Nice's problems with extremism.
It's not immediately known how Mohamad Lahouaiej Bouhel, the 31-year-old French-Tunisian and local resident who was named as the attacker in Nice, fitted into that picture.
Nice, France's fifth most populous city, is among many in the country struggling with an apparent lack of integration between longstanding residents and migrant populations mainly with roots in North Africa.
Radical recruiting grounds
In late 2015, Nice was prominent among cities reportedly
listed by French counter-terrorism experts as hotbeds of Islamic extremism.
Ariane, a densely populated neighborhood of high-rise apartment blocks to the north of Nice, was listed among 64 so-called "ghettos" characterized by youth unemployment and immigration.
Drugs and organized crime are also said to be part of a landscape seen as an ideal recruiting ground for radicalization, chiefly by the so-called Islamic State or ISIS group.
"From Nice, dozens of people have gone to join Islamic State in Syria and Iraq," said Prof. Peter Neumann of the International Centre for the Study of Radicalisation and Political Violence at Kings College London.
While the Nice attack has prompted some in France to call for tougher frontier controls and stricter limits on migration -- concerns frequently raised in European nations with open borders -- Neumann says much of the trouble is homegrown.
France's Mediterranean Riviera -- including Nice's neighbor Cannes, where movies stars gather every year for a glitzy festival -- is a key focal point, Neumann added.
"We also know that close to Nice, in Cannes, we had the first plot really after IS emerged early in 2014," he told CNN. "It's known that a number of people have gone from Nice and there are networks active that have recruited people."
That plot was behind a dramatic operations by French security service
in February 2014 in pursuit of Ibrahim Boudina, a French national born in Algiers, who was suspected of being a member of a terrorist cell behind a grenade attack in Paris.
Boudina, according to French security officials, was among members of a close-knit radical circle based around Cannes with links to other attacks and other extremists, particularly in the Paris suburb of Torcy.
According to CNN terrorism analyst Paul Cruickshank, French officials called the "Cannes-Torcy" group the most dangerous terrorist cell uncovered in the country since a 1995 bombing of the Paris metro.
Cruickshank reported that a friend interviewed by police portrayed Boudina as a leading figure in a small group of like-minded radicals who hung out together after prayers in mosques in the Cannes area.
Attracted by others from tougher immigrant neighborhoods, they were said to have gathered at a nearby river because the beaches of the Cote D'Azur were inappropriate because of scantily-clad women.
After heading to Syria in 2012, Boudina was detected re-entering Europe in 2014 and placed under surveillance as he hid out in Nice.
He was arrested in a raid on his parent's apartment block in Mandelieu-La Napoule, to the west of Cannes, despite trying flee the pursuit of security forces.
Following his capture, police later discovered a gun and bomb-making ingredients in the building -- cans filled with the high-explosive compound TATP with screws and nails for shrapnel.
Similar equipment was later used to deadly effect in the terrorist strikes in Paris and Brussels.