French President Emmanuel Macron has called for calm after a Corsican independence figure died of his injuries following a prison attack.
Yvan Colonna died on Monday evening in a Marseille hospital, three weeks after he was assaulted by another prisoner.
The nationalist figure had been serving a life sentence for the 1998 murder of Claude Érignac, a senior Corsica official.
Colonna -- who had always denied the charges -- was arrested in 2003 after a five-year manhunt that eventually found him living as a shepherd in the Corsican mountains.
According to investigators, the 61-year-old was strangled by a "jihadist" inmate at the prison gym in Arles on 2 March and was left in a coma.
A 36-year-old -- who had been imprisoned for "terrorist criminal association" -- had been charged with attempted murder.
When questioned, he accused Colonna of "blaspheming" the prophet Muhammad.
The violent attack sparked widespread anger on Corsica, with rioting and clashes between police and demonstrators.
Independence campaigners on the island had long called for Colonna to be transferred from a mainland prison and have accused France of "state responsibility" over the attack.
Tensions over the assault on Colonna culminated in riots in Bastia on March 13, which left 102 people injured, including 77 police officers. French officials have voiced concerns that his death could spark further violence on the Mediterranean island.
In Ajaccio, several hundred protesters gathered for a peaceful demonstration on Tuesday after Colonna's death.
Some lit candles in front of the city's cathedral, while others held a banner reading "Yvan martiriu di à causa corsa" ("Yvan is a martyr for the Corsican cause").
"His death is an injustice and a tragedy, which will mark the contemporary history of Corsica and its people," tweeted Gilles Simeoni, president of the Corsican Executive Council.
Colonna's killing has also prompted tributes from Spain, including from the National Assembly of Catalonia and Basque country officials.
The incident has also prompted fresh debate about Corsican autonomy, ahead of next month's French presidential election.
President Macron called for "calm and responsibility" in Corsica and assured that Colonna's death would have "consequences".
"The most important thing is that calm is maintained," he told France Bleu on Tuesday.
French government spokesperson Gabriel Attal has promised that an investigation will "shed light on events which led to this unacceptable situation".
French Interior Minister Gérald Darmanin had spent three days on Corsica in an attempt to quell anger, while Colonna’s prison sentence was suspended for "medical reasons".
But Macron's presidential rivals have accused the government of weakness in the face of violence and inaction over the past five years.
"Many questions" have been raised by the "circumstances" of the attack, said far-right National Rally candidate Marine Le Pen.
Meanwhile conservative candidate Valérie Pécresse urged for "a return to order in Corsica"
"I call on all our Corsican compatriots to be calm and restrained," she said on Monday evening.