A person known to the French authorities as a radical Islamist with mental health troubles stabbed a German tourist to death and wounded two people in central Paris on Saturday before being arrested, officials said.
The attack took place close to the Eiffel Tower during a busy weekend night and came with the country on its highest alert for attacks as tensions rise against the background of the war between Israel and Hamas.
"We will not give in to terrorism," Prime Minister Elisabeth Borne wrote on X, formerly Twitter, after the attack.
President Emmanuel Macron said he was sending his condolences to the family of a German killed in the "terrorist attack".
French anti-terror prosecutors said that they would now take on the investigation.
The attacker was known to authorities as a radical Islamist and was being treated for mental illness, Interior Minister Gerald Darmanin said at the scene by the River Seine, adding that the man had shouted "Allahu Akbar" ("God is greatest") before being arrested.
He fatally stabbed the German tourist, born in 1999, with a knife and then used a hammer to attack others as he sought to escape on the other side of the River Seine.
The area by Bir Hakeim bridge, usually thronging with tourists and locals, was cordoned off by police and bright with the flashing lights of security forces and emergency services.
'Violently threatened them'
The Paris prosecutor's office said the attacker, born in 1997, is French and has been arrested in an investigation into murder and attempted murder.
Darmanin said the man had already been sentenced in 2016 to four years in prison for planning another attack which he failed to carry out.
"A man attacked a couple who were foreign tourists. A German tourist who was born in the Philippines died from the stabbing," he said.
A taxi driver who witnessed the scene intervened, Darmanin said. The attacker then crossed the Seine attacking others and injuring one with a hammer.
Police chased in pursuit and used a taser to neutralise the man, who was then arrested.
"He had threatened them very violently... he will now have to answer for his actions before justice," Darmanin said.
The suspect, who lived with his parents in the Esonnne region south of Paris, told police he could not stand Muslims being killed in "Afghanistan and Palestine", according to the minister.
Macron, writing on X, thanked security forces for their quick arrest of the suspected attacker and said justice should be served "in the name of the French people".
"Paris is in mourning after this terrible attack," Transport Minister Clement Beaune wrote on X.
Joseph, 37 years old, a supermarket manager who asked not to give his last name, witnessed the scene, as he sat in a bar.
He heard screams and people shouting "help, help" as they ran. A man wielding an object attacked a man who had fallen down, and within 10 minutes the police arrived, he told AFP.
The country has suffered several attacks by Islamist extremists, including the November 2015 suicide and gun attacks in Paris claimed by the Islamic State group in which 130 people were killed.
There had been a relative lull in recent years, even as officials have warned that the threat remains.
But tensions have risen in France, home to large Jewish and Muslim populations, following Hamas's attack on Israel on October 7 and Israel's bombardment of the Gaza Strip.
Security in Paris is also under particular scrutiny as it gears up to host the 2024 Summer Olympic Games.
In October, teacher Dominique Bernard was killed in the northern French town of Arras by a young radicalised Islamist from Russia's Caucasus region.