A court in Paris has convicted two former skinheads for the murder of an 18-year-old anti-fascist activist in a June 2013 street brawl which led to protests and the banning of three extreme-right groups.

Esteban Morillo was sentenced to 11 years in prison on Friday after he admitted dealing the fatal blows that left student Clement Méric brain dead.

Samuel Dufour, who was by Morillo’s side but did not hit Méric, received a seven-year term. The men will appeal against the sentences, their lawyers said. A third man, Alexandre Eyraud, was acquitted of violence against Méric’s friends.

Méric’s parents welcomed the ruling. “The court’s decision establishes who is responsible, and makes an end to the lies about Clement’s behaviour,” said his father Paul-Henri Méric. “There were aggressors and there were victims.”

The prosecution had requested a 12-year sentence for Morillo for what it called an act of savagery, and seven years for Dufour.

“Incarceration is never victory,” said Méric’s mother Agnes. “What is needed is to continue to fight against the breeding grounds of the extreme right.”

Several hundred anti-fascists gathered in Paris for the verdict, chanting: “Clement! Clement! We do not forget, we do not forgive.”

The death of Méric, an 18-year-old politics student who had survived childhood leukaemia, shocked France and led to demonstrations against what was seen as a resurgence of far-right and neo-Nazi groups. The government moved to ban three groups that it described as “private militias” which “provoked discrimination, hate and violence”.

Lawyers for Méric’s family say the student was deliberately attacked and the incident was not merely a street brawl.

The altercation began at a private clothing sale in an apartment in a busy shopping area behind Paris’s big department stores where the main attraction was the British label Fred Perry. Its polo shirts were highly sought after in France by skinheads as well as leftwingers and mods.

A few hard-left anti-fascist activists at the sale rebuked a handful of skinheads who were wearing “white power” and “blood and honour” T-shirts. Outside, the confrontation turned violent and Méric sustained severe injuries. He died in hospital the next day.

Méric had not been violent but had “refused to lower his gaze”, according to one of his friends, adding: “If Clément is dead it was because he was anti-fascist. This was a political murder, not a fight between gangs.”