Paris (AFP) - President Emmanuel Macron on Wednesday hailed a policeman who sacrificed his life in an Islamist attack as a symbol of the "French spirit of resistance" and urged the nation to be vigilant in the face of an "insidious" jihadist threat.
"The name of his attacker will be forgotten, but the name of Arnaud Beltrame will live on," Macron told a national ceremony to honour the officer, one of four victims of Friday's shooting spree in southwestern France.
The French leader vowed to ensure "he will not have died in vain".
"His example will remain etched in French hearts," the president told hundreds gathered in the rain at the historic Invalides military museum and hospital in central Paris.
Beltrame, a 44-year-old member of the gendarmerie military police force, died offering to take the place of a female checkout worker whom attacker Radouane Lakdim was using as a human shield at a supermarket in the town of Trebes.
Lakdim, who claimed allegiance to the Islamic State group, had already shot dead the passenger of a car he hijacked in nearby Carcassonne, before driving to the supermarket and killing two more people there.
Beltrame hoped to be able to negotiate with the 25-year-old, but Lakdim stabbed him in the throat and the officer died of his wounds the next morning.
His coffin lay draped in the French flag on a wooden bier in the vast cobbled courtyard of Les Invalides during Wednesday's ceremony.
Contrasting the deaths of Beltrame and his killer Macron said Lakdim had died "a cowardly death obtained through the murder of innocents".
After the worst attack of his presidency so far, he urged heightened vigilance against Islamic extremists who have claimed more than 240 lives in France over the past three years, including the massacres in Paris and Nice.
"We are not just fighting terrorist groups, the armies of Daesh and imams who preach hate and death," Macron said, using another name for the Islamic State group.
France is also facing a form of "underground Islamism" that "corrupts on a daily basis", he said, blasting it as "an insidious enemy which requires renewed vigilance and civic-mindedness from every citizen".
- 'Man with a big heart' -
Thousands of people lined the streets as Beltrame's funeral cortege made its way through Paris for the ceremony.
"It's important for me to be here to pay tribute to all the police officers who protect us on a daily basis and risk their lives for us," said 64-year-old Andree.
Some 400 people including former presidents Francois Hollande and Nicolas Sarkozy attended the ceremony, where Beltrame was posthumously made a Commander of the Legion of Honour and promoted to the rank of colonel.
His widow Marielle and other family members were also at the ceremony, along with relatives of Lakdim's other victims, including four people wounded in the shooting spree.
Across the country, police stations paused for a minute's silence at 10.00 am.
Family members have said it was typical of Beltrame, who trained as a paratrooper and served in Iraq, to put others first.
"You behaved in your last moments just as you behaved throughout your whole life: as a patriot, as a good man, as a man with a big heart," his brother Damien wrote on Facebook.
Flowers have been piling up outside his local gendarmerie base in Carcassonne, where a note on one bouquet read: "Thanks to you, Arnaud, France is beautiful."
Rightwing opposition leader Laurent Wauquiez and far-right leader Marine Le Pen have accused the government of a laxist approach to the jihadist approach.
The government has rejected criticism that the attack could have been prevented through tougher measures such as the preventive detention of known extremists.
Lakdim, who had previous convictions for drug use and handling a banned weapon, had been on a list of suspected extremists since 2014 and was being monitored.
"There is a clear refusal to accept that Islamic fundamentalism has declared war on France," Le Pen told Sud Radio on Wednesday.
Prime Minister Edouard Philippe has hit back at politicians who "promise people zero risk", and rejected hardline proposals from rightwingers such as an outright ban on ultraconservative Islam.
France already has "a legal arsenal" to "understand, monitor and sanction" extremists, Philippe said.