So-called Islamic State says it was behind deadly gun attacks in southwestern France on Friday in which a man shouting "Allahu Akbar" stormed into a supermarket and took hostages.
The lone gunman was shot dead when security forces raided the store in the small town of Trèbes after a siege.
By that time, however, he had killed a total of three people and injured 16 others.
The French police officer who volunteered to trade places with a hostage during the siege has died, said Interior Minister Gerard Collomb on Saturday.
45-year-old lieutenant colonel Arnaud Beltrame offered to trade places with a hostage, said Collomb, in what he described an 'act of heroism'.
According to Collomb, he had a call running on his mobile phone throughout the attack to allow police units to monitor the situation inside the supermarket.
"And so he stayed with him. The terrorist opened fire. The tactical unit intervened. And shot down the terrorist."
Beltrame died of his wounds, becoming the gunman’s fourth victim.
Speaking from the Elysee presidential palace, Macron praised the “exceptional courage” of Beltrame.
"At the heart of the action, Lieutenant-Colonel Beltrame has shown exceptional coolness and illustrated the military virtues in a vivid manner, which deserves the respect and admiration of the entire nation."
Beltrame’s name was the top trend on Twitter on Saturday, with people posting their respects for the fallen officer.
Brother of Arnaud Beltrame speaks out
Speaking to RTL radio, Beltrame's brother said that he had died a hero and "gave his life to strangers."
"He was well aware he had almost no chance. He was very aware of what he was doing," he said, adding that if his brother was described as a hero, he didn't know what a hero was.
"It's a word I think is appropriate for him in such tragic circumstances."
Supermarket manager describes attack as "terrifying"
The manager of the Super U supermarket that was attacked by an extremist gunman praised Beltrame as a hero for exchanging himself for a hostage.
The manager, who only identified herself as Samia, said that her co-worker was in a "catastrophic state" after the death of Beltrame.
Samia said she was in her office when she heard gunshots. She went downstairs to see what was going on and saw the attacker firing gunshots and yelling "Allahu akbar". Samia says she ran upstairs and told her co-workers to call the police and started evacuated people from the emergency exit.
"It was terrifying," she said.
The gunman, named as local man Redouane Lakdim, 25, of Moroccan origin, was known as a petty criminal.
However, Paris Prosecutor Francois Molins revealed on Friday night that Lakdim had been monitored by security services for links "with the Salafist movement".
Molins said that when Lakdim entered the shop, in which some 50 people were present, he claimed to be a "soldier" of Daesh (Islamic State), ready to die for Syria.
He also demanded the liberation of 'brothers' before shooting dead a customer and a member of staff.
Initial media reports suggested Lakdim demanded particularly the release of Salah Abdeslam - the prime surviving suspect in the ISIL attacks that killed 130 people in Paris in 2015.
Molins also revealed that Lakdim had threatened to blow up the store before security forces moved in.
Before seizing hostages, Lakdim had already shot one person dead and injured another while stealing a car on Friday in the nearby town of Carcassonne, which is one of France's top tourist attractions.
He then shot at four police officers who were jogging, injuring one of them, before taking hostages at the supermarket in Trèbes, about 8 km to the east, where two people died.
The Portuguese government indicated on Friday night that a Portuguese citizen was among those killed in the attacks.
Two people with links to Lakdim detained by police
Police detained a 17-year-old in connection with the investigation into the ISIL-claimed attack that killed four people, including a police officer, said the Paris prosecutor's office.
The unidentified young man, who was a friend of Lakdim, is believed to have links to the Trebes supermarket attack.
Paris prosecutor Francois Molins added police had also detained a woman close to Lakdim. The unidentified woman was taken into custody on the same grounds.
More than 240 people have been killed in France in attacks since 2015 by assailants who pledged allegiance to so-called Islamic State or were inspired by the group.
The last deadly attack in France was in October 2017 when a Tunisian-born man stabbed two young women to death in Marseille before he was shot dead by soldiers. ISIL also claimed responsibility for that attack.