The victim is 31-year-old Mamoudou Barry, a researcher and teacher from Guinea, who had just completed his PHD with flying colours. He was brutally attacked on Friday night by a man hurling racist insults.
Barry had gone to pick up his wife at the bus stop after work and had then planned to watch the final of the Africa Cup of Nations football tournament, in which Algeria was taking on Senegal.
As they were preparing to drive back, a man approached their vehicle. According to Barry's relatives, the attacker pointed his finger at him and said in French: "You, black bastards, we are going to kill you tonight."
When he got out of the car to ask why he was being insulted, he was beaten unconscious, and as he fell he hit his head on the pavement.
He was rushed to hospital but succumbed to his injuries 24 hours later.
Interior minister Christophe Castaner tweeted that "everything will be done to identify and arrest the author of the attack. It is up to the justice system to provide a full account of this heinous act".
Tout est mis en œuvre pour identifier et interpeller l’auteur de l’agression qui a coûté la vie à #MamadouBarry.Christophe Castaner (@CCastaner) July 21, 2019
Il appartiendra à la Justice de faire toute la lumière sur cet acte odieux.
Mes premières pensées vont à ses proches dont je partage l’émotion et l’indignation.
Outrage and conspiracy theories
The attack sparked a flurry of reaction on social media, with initial responses suggesting that the racist insult was harmless football banter.
Other comments claimed Barry had been attacked by an Algeria supporter who had mistaken him for a Senegal fan.
Barry's lawyers said there was no doubt that the act was a "racist crime", though they would not link it to the African Cup of Nations.
"We are shocked...we can't even ask his wife about this because she is traumatised," said Fatou Barry, Mamoudou's aunt, who told RFI she fears that such comments could enflame racial tensions between Arabs and Africans in France.
"There are people posting videos of Arabs killing Africans, with the photo of Mamoudou. When I saw that, I was deeply hurt," she said. "We want justice for Mamoudou not war between the two communities," she insisted, warning the public not to be fooled by hate-driven propaganda.
The theory that Barry was killed as a result of Arab-African hostility, was cast into doubt Monday morning after police arrested a man of Turkish origin.
The suspect is 29 and according to police has psychiatric problems. He is known to authorities for drug-related offences and petty crime. He is originally from Canteleu, the suburb in Rouen where the incident took place but no longer lives there. He was found using CCTV and witness statements.
"I don't know why this man did this, why he used such hateful language. Only God knows," commented Fatou.
The research institute Thinking Africa, where Barry worked, wrote Monday that they had lost a much-loved colleague.
Barry had just completed a doctoral thesis on tax and customs policies for foreign investment in francophone Africa.
"He impressed the jury so much that they gave him a distinction for his work despite the fact that since May 2016 French universities no longer award honours for theses," said Adam Abdou, one of his colleagues.
"The jury said he was the only specialist in his field. We are all in shock, teachers and students alike. We have lost an exceptional person who was open-minded and loved everyone," he told RFI.
A march to pay tribute to Barry has been organised in Rouen for Friday at 15:00 and in Paris on Saturday at 13:00.