A STUDIOUS 15-year-old pupil from the south of France, Adèle enjoyed biology and dreamed of saving lives. But she led a double life. In one Facebook identity she was just a teenaged girl. In the other she was Oum Hawwa, chosen by Allah to help “brothers and sisters” in Syria. Early this year Adèle failed to come home, flew out of Marseille and made it to Syria. Her family says she is now a hostage of jihadists.

Such stories have become more common as France, home to Europe’s biggest Muslim minority, struggles with the flow of would-be jihadists to Syria and Iraq. Bernard Cazeneuve, the interior minister, reckons 930 French citizens are either already there or trying to go. Another 36 have died fighting. Although on a per-head basis its jihadists are outnumbered by Belgian and Danish ones, France supplies the largest single contingent. Almost a fifth are female. Some entire families have gone.

Most French jihadists are recruited through one of two routes, says Dounia Bouzar, author of “They Sought Paradise, They Found Hell”, a new book that traces the paths of those like Adèle. Young men, many of whom might have joined the police or the army and have “a tormented relationship with their virility” are, she says, seduced by the promise of a mission and a purpose free of Western lies. The appeal to young girls, by contrast, is often a humanitarian desire to help innocent children; many female recruits hoped to be nurses, doctors or social workers.

A striking feature of this new wave, says Mr Cazeneuve, is its “self-service” nature. Individuals reach jihadist recruiters in a few internet clicks or on social media, and can be on a low-cost flight via Turkey in no time. Jihad also holds appeal for middle-class teenagers and non-Muslims. The government says almost half of French jihadists were previously unknown to the police, and 20% are converts. Of the 130 families who have contacted an early-warning centre set up by Ms Bouzar, 70% are non-believers, few have much knowledge of the Koran or Arabic, and many come from middle-class families.

France has long been unapologetically tough on terrorism, and the police have sweeping rights to detain and charge suspects. But the French have felt disarmed in the face of the casual departure of youngsters on cheap flights to Turkey. The wake-up call was the arrest in Marseille of Mehdi Nemmouche, a Frenchman now in custody in Belgium, who is suspected of shooting dead four people at a Jewish museum in Brussels in May after fighting for Islamic State (IS) in Syria.

Mr Cazeneuve is now pushing a tough new counter-terrorism law through parliament. It turns individual terrorist intent into a criminal offence (the current law requires “association” with others) and makes it possible to stop suspects from leaving France if there is “serious reason” to believe their trip is linked to terrorist activity. Although this gives counter-terrorism authorities considerable preventive powers, and civil-liberties groups have criticised some provisions, the bill enjoys broad cross-party support.

The main reason for this political consensus is that the French are on high alert over the terrorist risk at home, thanks to the return of people like Mr Nemmouche. France’s participation in air strikes against IS in Iraq has made it a target. In September Hervé Gourdel, a Frenchman, was beheaded in Algeria by a terrorist group linked to IS. Some 119 terrorist suspects have been arrested in France, 81 charged and 56 jailed. When asked by a recent visitor what keeps him awake at night, Manuel Valls, the prime minister, replied: terrorism.