According to university officials and the French government's spokesman, the man who attacked police officers patrolling in front of Notre Dame Cathedral, crying out "This is for Syria!", was a former journalist who was working on a doctoral thesis and had not been suspected of radicalisation.
Christopher Castaner told RTL radio on Wednesday that police were quickly able to classify the hammer attack as a "terrorist act" because of "the words he said."
Surveillance video emerged on Wednesday showing the man lunging at officers on the plaza outside the cathedral, then being shot to death, according to the footage provided to The Associated Press.
An officer was slightly injured in the attack on Tuesday and the attacker remained hospitalised after being shot by police. Police have not released his name.
No group immediately claimed responsibility, but police searching the man's residence outside Paris found a declaration of allegiance to the Islamic State group, according to the Paris prosecutor's office.
A student identity card showed he was from Algeria and 40 years old.
The university of Lorraine's president, Pierre Mutzenhardt, told France Bleu radio that the man was enrolled as one of its students and had been working since 2014 on a thesis about North African media. He said the man previously worked as a journalist for North African media.
"There'd been no difficulties with him. Nothing strange had been detected", he said.
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His thesis director, Arnaud Mercier, told broadcaster BFM that the suspect spoke Swedish, Arabic and French and that his resume mentioned that he had worked as a journalist in Sweden and Algeria.
"He was someone who believed a lot in democratic ideals, the expression of free thinking in journalism", Mercier saidon BFM. "Nothing, absolutely nothing, foretold that one day he'd be a jihadi who'd want to kill a policeman in the name of I don't know what cause."