In this Paris suburb often dubbed "Little Jerusalem" for its vibrant Jewish community, a climate of fear is taking hold as police expose networks of Islamic extremists planning anti-Semitic attacks.
Sarcelles, a community of 60,000 in the northern suburbs of Paris, has been at the centre of an investigation into Islamist groups after the bombing of a Jewish grocery here last month.
French police at the weekend launched a nationwide sweep that left one man dead and 12 others in detention on suspicion of either being involved in the grenade attack on the shop or of planning other anti-Semitic attacks.
Interior Minister Manuel Valls on Monday predicted more arrests and warned of possibly hundreds of home-grown militants at large.
At the Naouri Market kosher grocery, residents said they were relieved at the arrests but increasingly afraid of being targets.
"We were expecting arrests at some point, but we would never have believed it would take on such proportions. I thought the grenade was thrown by two isolated individuals," said Sylvie Journo, a mother of four in her 40s.
Jewish community leaders have warned of a rise in anti-Semitic attacks in France before and after the March shooting rampage of Islamic extremist Mohamed Merah that killed three Jewish schoolchildren, a rabbi and three paratroopers.
With the most recent arrests, Journo said: "We have the impression that there are Mohamed Merahs everywhere."
Standing nearby in the grocery, pensioner Mireille Hayoun agreed.
"We are glad that the Islamists were arrested but this won't stop the attacks from continuing. We're even afraid they will get worse," she said.
Richard Prasquier, the head of the CRIF, the main representative body for French Jews, said Monday that Islamic radicalism was akin to Nazism and warned that French society had not yet realised "the scale of the evil" it faces.
"Radical Islam considers its enemies animals: Jews are sons of monkeys, Christians are sons of pigs, everyone are sons of dogs -- in the same way the Nazis compared Jews to a parasites, to rats," he said.
France's SPCJ Jewish security watchdog said Monday that anti-Semitic acts had increased 45 percent in the first eight months of 2012 from the same period in 2011, with 386 registered.
Of those, 101 were violent, including four murders, one attempted murder, 56 attacks, 39 acts of vandalism and one attempted arson, the SPCJ said, warning of a new "impetus" following Merah's attacks and "increasingly violent" acts in recent months.
President Francois Hollande has vowed to boost security at Jewish sites and on Monday police strengthened patrols around a synagogue in the Paris working-class suburb of Argenteuil, where blank shots were fired at the building on Saturday.
"Their presence is reassuring. It will discourage those who may want to commit attacks," said Roger Touati, a member of the local Jewish community.
In Sarcelles, local rabbi Laurent Berros said the Jewish community was comforted by the fact that none of those arrested were from the area, a mixed district home to many different ethnic and religious groups.
The suspected leader of the ring behind the grenade attack, Jeremie Louis-Sidney, 33, was killed Saturday after he opened fire on officers seeking to arrest him in a dawn raid at his home in Strasbourg, eastern France.
Subsequent police raids on addresses in the Paris region and in the Riviera resort of Cannes resulted in 12 suspects being detained.
"What reassured us was that... the perpetrators of the attack were not from the city. The link between the different communities was not broken," Berros said.
"But what is more worrying is to know that the alleged perpetrators of the attack were not isolated individuals," he said. "We really feel like we are the targets of madmen."