The French interior minister, Bernard Cazeneuve, paid a visit before the market opened, and the employees, all new, were met by crowds of reporters as they hurried in to get ready for business.
Shoppers were there as much to pick up matzo, hummus and ceremonial candles as to show support.
"Being here now is an act of conscience," Annie Boukobza, 60, said outside the market. "We have to show the world we are here."
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Ms. Boukobza said she had shopped at the supermarket an hour before Amedy Coulibaly, a 32-year-old Frenchman who claimed to be affiliated with the Islamic State, stormed in, holding employees and shoppers hostage. Four people were dead before the police launched an assault and killed him.
Among those killed by Mr. Coulibaly was Yohan Cohen, 22, one of the employees. A new employee, who was busily stocking shelves and did not provide her name, said none of the former workers had returned. "They did not want to work here any more," she said.
Ms. Boukobza said people were still traumatized by the attack. She said that when she heard that the supermarket was the scene of an attack, she helped evacuate a nearby Jewish school. "Children were very affected that day," she said.
The attack was part of a three-day assault in and around Paris that began with a spray of bullets at the satirical newspaper Charlie Hebdo on Jan. 7. When the rampage was over, 17 people were dead, including three gunmen, all French citizens who said they were supporters of Islamic extremist groups.
The assault on the market, which is in eastern Paris and a short walk from the Place de la Nation, stoked fears among some Jews in France about their safety, fears that had grown in the aftermath of other attacks on French Jews in recent years, as well as a rash of anti-Semitic acts last year.
Prime Minister Benjamin Netanyahu of Israel, visiting Paris after the Charlie Hebdo attacks, urged French Jews to move to Israel, "their home." He repeated his invitation after a terrorist attack in Copenhagen on Feb. 14 that also targeted Jews, saying European Jews would be welcomed "with open arms."
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Prime Minister Manuel Valls of France responded with an emphatic speech, insisting that "France without French Jews is not France." Mr. Cazeneuve's visit to the market on Sunday was meant to reinforce the government's commitment.
A passer-by, Yves Harroch, 24, said he was nevertheless worried. Mr. Harroch said he had considered moving to Israel, a place where he thought he could find "an ideal of life."
"But not because of fear," he added.
Léon Gelbart, 49, and Mickaël Peres, 39, friends who live in the neighborhood, said they had been regular shoppers at the market. They shrugged off some of the fears.
Mr. Gelbart called the neighborhood "a very pleasant place to live" and noted that French Jews had weathered other anti-Semitic periods. "And there will surely be more, unfortunately," Mr. Peres added.
But Mr. Gelbart and Mr. Peres said they had not considered leaving Paris.
"We live well here," Mr. Gelbart said. "We love Israel, but we also love France."
Mr. Gelbart added: "We're French, after all. Jewish and French."