Best known as a Riviera tourist destination, Nice has been struggling to get a grip on its less prized distinction as France's prime recruiting ground for would-be jihadis.
France's anti-terror prosecutors said on Friday they were looking for terrorist ties after a gunman plowed a delivery truck into crowds gathered to watch Bastille day fireworks, killing at least 84.
The hinterlands beyond the smart streets of the old city have seen dozens of its Muslim residents head to Syria in recent years to fight.
"Nice is the city which has been most hit by the jihadist phenomena," said David Thomson, an expert on radicalization in France.
"There is one main reason behind it: since 2010, a charismatic character, known as one of the main recruiters of French jihadists, has been hugely active preaching in poor neighborhoods," Thomson said.
The militant in question is Omar Diaby, a former Nice resident of Senegalese origin now believed to live in Syria who made a name for himself in 2012 with a series of online propaganda videos entitled "19HH".
The French administrative department of Alpes-Maritimes, of which Nice is the capital, said at the end of last year that 236 individuals had been monitored over several months as part of a surveillance program and that it was tracking five new individuals every week.
The region of just over a million people is thought to be home to 10 percent of all of French citizens gone abroad to wage jihad. Back in 2014 the regional government cited one case where 11 members of a single family were reported missing, believed to have left for Syria.
Flags fly at half-mast in memory of victims the day after a truck ran into a crowd at high speed killing scores and injuring more who were celebrating the Bastille Day national holiday, in Nice, France, July 15, 2016.
But there have been successes as well: that same year, police said they foiled an imminent attack targeting Nice's carnival, one of the world's biggest after those in Rio de Janeiro and Venice.
Since a nationwide state of emergency was declared after the Nov. 13 shootings and bombings in Paris, the regional government has shut down five illegal religious centers on the suspicion they were used to foment extremism.
Nice's jihadi problem is all the more striking as it is one of the most heavily policed cities in France and closely monitored by an extensive video surveillance system due to the efforts of its security-obsessed former mayor Christian Estrosi, now the president of the broader Riviera region and beyond.
Since February 2015, the Alpes-Maritimes department has been running a program to train 1,300 social and medical workers to identify people that may be tempted by radicalization.