PARIS — At the Fresnes detention center in the southern outskirts of Paris, Islamist prisoners disrupted the national moment of silence observed in honor of the victims of the massacre the previous day at the Charlie Hebdo offices. The staff was gathered in the main prison courtyard when inmates pushed the volume of their television to the maximum. Others blared music. Through the bars of several cells, radicals shouted, "Allahu Akbar. Those dirty infidels, they deserved it." Visiting hours had just finished. Families heading to the exit joined in with the "disruption chorus," a prison official says.

About 50 of the prison's 2,000 inmates were among those disrupting the national day of mourning. The Fresnes prison is the second largest in Europe after the Fleury-Mérogis prison, also in the southern outskirts of Paris, which counts 4,000 inmates.

The latest incident wasn't a riot, just a conspicuous sign that Islamist proselytism is still persistent in French prisons. "There's not a single institution that, every single day, is not confronted by an act of proselytism that plagues the penitentiary life," says Emmanuel Gauthrin, secretary-general of "FO pénitentiaire," a national penitentiary union. 

For a long time, the issue was confined to other French central institutions in the towns of Lannemezan, Saint-Maur, Clairvaux, Arles, Yzeure, Condé-sur-Sarthe and a few others. They are prisoners designed for long sentences, particularly for the Islamist terrorists of the 1980s and 1990s, including those of the Armed Islamic Group (GIA), an Algerian organization that perpetrated attacks in France in 1995 and 1996.

Fouad Ali Saleh, also known as "Ali the Tunisian," was sentenced to life in April 1992 for plotting some 15 bombings, including the September 1986 one at rue de Rennes in Paris that killed seven and wounded 54.

He has often been placed in solitary confinement because he threatened to cut the throat of his fellow North African inmates, saying they were too "weak" in their practice of religion. The guards who follow him closely say he is far from reformed. "In 20 years inside, he hasn't changed."

Lionel Dumont, founder of the "Gang de Roubaix," in his hometown, which is made up of several converts to Islam, is among the most influential inmates. Considered by the guards as "one of the most vindictive," he is serving a 30-year sentence for a series of robberies meant to finance the Islamist cause. "The converted are the most dangerous because they have the most to prove," says the FO pénitentiaire's James Vergnaud.

An epidemic

Over the past dozen years, radical Islam has spread like an epidemic in detention centers that receive people awaiting a final judgment or who are sentenced to short prison terms. Fleury-Mérogis and Fresnes were no exceptions. That's where Chérif Kouachi was kept in custody from November 2005 to October 2006. It was there that he met a figure of French radical Islam, Djamel Beghal. It was the same for the penitentiary institutions that, in their time, received Mohammed Merah, the French-Algerian Islamist terrorist responsible for the March 2012 killings in Toulouse and Montauban, who was killed in the raid launched against him. And it was the same story line for Mehdi Nemmouche, a Frenchman accused of murdering four people at the Jewish Museum of Belgium in Brussels in May 2014.

According to an October 2014 report published by Guillaume Larrivé, a parliament member from the center-right party Union for a Popular Movement, 40,000 inmates can be considered "of Muslim culture and religion." Jewish inmates, meanwhile, are few in number and are systematically isolated in order to guarantee their safety. In Moulins-Yzeure, the prison's two Jewish suspects (among 135 prisoners) were counseled not to use the soccer field. Meanwhile, the gym room is opened just for them at certain hours.

The information concerning the identity and lifestyle of inmates, which are noted when they enter the detention system, allows authorities to judge who has a dangerous profile. The surveillance staff are then on the front line, especially since the penitentiary administration has an internal intelligence service that Justice Minister Christiane Taubira reinforced in 2013. Its 80 or so members work closely with the intelligence services of the Ministers of the Interior and of Defense, and receive training to detect "deviant behaviors." This is a term that includes radical Islamists, potential jail breakers and mafia-related profiles.

"We should know exactly how many there are, but if you ask, people think you're a foul racist," one prison warden says.

Containing the spread

In an attempt to contain the epidemic, the Fresnes prison director tried an experiment in early December to put the most radical inmates — around 50 Islamists — on the same floor. Other prisons could follow the strategy if it proves to stem growth of Islamist proselytism.

Radicalization used to reveal itself through a series of external signs, such as the refusal by Islamist inmates to speak to the female staff. "Being a woman, in addition to being Muslim, isn't easy," explains Fadila, a dynamic 40-year-old warden who has worked for more than 15 years in sections that receive men and minors.

"When I worked in Poissy [in the northwestern outskirts of Paris], a fundamentalist Muslim refused to speak to me because I was a woman of North African descent," she recalls.

Among other visible signs of radicalism are attempts to establish group prayers — which are forbidden — during exercise time, or calls to follow the rite through cell windows. In Lannemezan, for instance, an al-Qaeda militant, who'd just preached in the courtyard, summoned his fellow inmates to tell them not to go back up in the corridors after the daily walk. 

Looking to "clash" with the prison wardens, whom radicals call "infidels," or "harkis" when they are of North African origin, is also part of the classic behavior of potentially troublesome Islamist inmates.

Recruiting grounds

Over the past few years, successive Ministers of Justice have supported the nomination of official imams to channel any excesses (there are now 169 in the prisons, compared to 655 for Catholicism). In practice, the newcomers have serious trouble establishing themselves against self-proclaimed preachers, some of whom behave like mob bosses.

In the Ensisheim prison, in eastern France, a warden heard an inmate say to another, "If you join our family, you'll never be alone. If your family is ever in need, we'll be there." Says the warden who witnessed the conversation, "When you're Muslim, you need to be strong not to give in to the ultras."

According to Jean-Michel Dejenne, secretary-general of the national union for penitentiary directors, the biggest problem used to be violent clashes among inmates. "Now, they've become recruiting grounds." Clashes may be less frequent, "but proselytism isn't decreasing. It’s just not as aggressive anymore," he adds.

The strategy to spread jihad now includes blending in. A few weeks ago, a 43-year-old Frenchman with Tunisian origins who'd just served out his sentence was noted for his good behavior. The only time he'd gotten into trouble was when he was caught praying away from everyone else. It was "not to bother anyone," he explained apologetically.

The wardens didn't make much of it. Upon his release, he was supposed to return to his home in Brittany. Instead, he went to Syria.