A memorial Mass has been celebrated in the southern French town of Trèbes, in honour of four people killed by an Islamist gunman on Friday.
One of them, policeman Lt-Col Arnaud Beltrame, has been hailed as a hero for trading places with a captive during a siege at a supermarket.
The bishop at the church told hundreds of mourners that his actions were comparable to that of a saint.
It is the worst jihadist attack under Emmanuel Macron's presidency.
The gunman, 25-year-old Redouane Lakdim, had been on an extremist watch list and was known to authorities as a petty criminal, but intelligence services had determined he did not pose a threat. He was shot dead by police.
Lakdim, who pledged allegiance to Islamic State militants, was said to have demanded the release of Salah Abdeslam, the most important surviving suspect in the 13 November 2015 attacks in Paris, which killed 130 people.
In the packed Church of Saint-Etienne in Trèbes, the bishop of Carcassonne and Narbonne compared the police officer's actions with those of a Polish saint who volunteered to die in the place of a stranger at the World War Two death camp at Auschwitz.
Mourners, which included members of the local Muslim community, lined the back and front steps of the church.
"Your presence tells us that the creators of hatred will not win," Bishop Alain Planet said to the Muslim congregates in his address.
Outside the 14th-century church, the local imam later said according to the news agency AFP: "The [Muslim] community has been stabbed, Islam itself has been stabbed... by people who use symbols that are dear to our hearts."
The chief of French police, Richard Lizurey, attended the service and later told reporters that Col Beltrame was an inspiration to those working in the French security services.
"It's an heroic act. In fact an exceptional act, carried out in the heat of action," the head of the Gendarmerie said. "We are proud. Proud to have counted Arnaud Beltrame among us."
The attack has shaken the rural town of 6,000 people, and flowers have been laid in front of the Super U shop where the hostage-taking took place, as well as outside Col Beltrame's police barracks. A separate national memorial in Paris will also honour the killed officer in the coming days.
Khadija, a 52-year-old restaurant owner, said she was shocked by what had occurred. "We thought this only happened in big towns," she told AFP.
Who were the victims?
Before the hostage-taking in Trèbes, Lakdim hijacked a car in nearby Carcassonne, shooting the Portuguese driver and killing passenger Jean Mazières, a retired winemaker in his sixties.
He organised villages fetes and was described as "very jolly" by Marc Rofes, the mayor of Villedubert, where his family lives.
"He loved life, he loved parties... we have lost someone who was liked by everybody," he said of Mr Mazières, who was married and had one child.
The driver of the car remains in a critical condition.
After opening fire on a group of police officers out jogging, wounding one, the gunman drove to the Super U in Trèbes, where he killed the shop's chief butcher, Christian Medvès.
An amateur runner and one-time local political candidate, Mr Medvès, 50, was described as having the "joy of life".
"We do not know yet what happened, but knowing Christian, I imagine he would have wanted to intervene," his friend Franck Alberti told local paper La Dépêche du Midi.
He was married with two daughters.
Retired builder Hervé Sosna, 65, was at the butcher's counter when Lakdim mounted his assault.
The Trèbes resident "had a huge intellectual capacity" and was a capacious reader, especially of poetry, his half-brother told La Dépêche du Midi.
"He never asked for anything, and he was killed, just like that."
The brave police officer has emerged as the human face of this attack, and his actions are being seen as a defiant response to the country's would-be attackers - a reminder of the best of France, says BBC Paris correspondent Lucy Williamson.
Although police managed to free hostages from the supermarket, Lakdim had held one woman back as a human shield, and Col Beltrame volunteered to swap himself for her.
As he did so, he left his mobile phone on a table with an open line so that police outside could monitor the situation.
When police heard gunshots, a tactical team stormed the supermarket. The gunman was killed and Col Beltrame, who was 44, was mortally wounded.
He and his wife, Marielle, had been married in a civil ceremony but were planning a church wedding in June. The Catholic priest who was meant to officiate at the ceremony visited Col Beltrame in hospital, where Marielle was keeping vigil, before he died.
World leaders, including UK PM Theresa May, have paid tribute to the officer, who was a highly-regarded member of the Gendarmerie Nationale and was described by President Macron on Saturday as someone who "fought until the end and never gave up".
"He gave his life for strangers. He must have known that he didn't really have a chance. If that doesn't make him a hero, I don't know what would," Col Beltrame's brother, Cedric, told a French radio station on Saturday.
Speaking to the BBC, Col Arnaud's cousin Florence Nicolic described the officer as a person who was "so good at his job".
"Even though we were surprised and shocked when we heard what happened we were not surprised in the sense that that's the thing he would do without hesitation," Ms Nicolic said.
Col Beltrame was deployed to Iraq in 2005 and was later awarded the Cross for Military Valour for his peacekeeping work. On his return to France, Col Beltrame joined the country's Republican Guard and was tasked with protecting the presidential palace.
In 2017, he was named deputy chief of the Gendarmerie Nationale in the French region of Aude.