Amine Kessaci, center, and his mother attend a gathering in homage to his brother Mehdi Kessaci at the roundabout where he was murdered, and to protest against drug trafficking, in Marseille, southern France, Saturday, Nov. 22, 2025. (AP Photo/Philippe Magoni)

Thousands of people marched Saturday in the French southern port city of Marseille to denounce drug trafficking after the killing last week of an activist`s brother shocked the country.

Mehdi Kessaci, 20, was killed in Marseille last week in a shooting officials have described as ordered by drugs criminals to frighten or punish his older brother, Amine, a prominent anti-drugs activist.

An estimated 6,000 people, many dressed in white, gathered behind a "Justice for Mehdi" banner, observing a minute of silence and later raising hands in a sign of rejection of drug violence. Some politicians from across the political spectrum joined the demonstration.

Amine Kessaci, 22, had called for the march to denounce drug trafficking and pay tribute to his brother. Similar gatherings took place Saturday in about 20 other cities across the country.

Earlier this week, Marseille prosecutor Nicolas Bessone said an investigation was open for "premeditated murder committed by an organized group." The probe`s main hypothesis is that Mehdi Kessaci was killed to try to intimidate his brother, he said.

Bessone said Mehdi had "nothing to do" with drug trafficking and was ambitioning to become a police officer. His brother Amine was "the target of threats and intense pressure" and was placed under police protection, he said.

Amine, who released a book denouncing drug violence in October, attended his brother`s funeral this week wearing a bulletproof jacket and under heavy police protection.

Amine lost another brother, Brahim, in an alleged drug killing in 2020, which prompted him to launch his association, Conscience, to support families impacted by gang violence. Brahim was involved in drug trafficking, Amine said.

Marseille has a long history as a hub for the drug trade and banditry associated with it.

In 2024, French authorities recorded 367 cases of murder or attempted murder, with 341 people injured and 110 deaths linked to drug trafficking. Of the 176 individuals jailed for murder and attempted murder, more than 25% were aged under 20, including 16 minors. In all, 47 tonnes of cocaine had been seized in 2024, more than double the previous year`s total.

Earlier this year, France`s government launched a campaign against drug use and trafficking to raise awareness among millions of recreational drug users that their habits are fueling gang violence and death.

France also passed a new anti-drugs law in June, which sets up a specialized prosecutors` office dedicated to organized crime, on the model of the counterterrorim prosecutors` office, amid other measures.

According to Interior Minister Laurent Nuñez, a government crackdown on drugs crime helped diminish the number of homicides in Marseille down from 49 in 2023 to 24 in 2024. The number of dealing points in the city had halved from 160 to 80, he said.

Mehdi Kessaci`s killing show drug gangs have reached "a new level of violence," Nuñez said.