Protesters clashed with police in southern France on Saturday over the death of activist Remi Fraisse, who was killed by a police grenade last month.

Police used water cannon and tear gas against the protesters and at least 16 were arrested in Toulouse after rubbish bins were set on fire and bus stops smashed.

The confrontation flared on the margins of an otherwise peaceful march where demonstrators waved placards demanding: “No firearms” and: “End the licence to kill.”

Student Mr Fraisse was killed last month during a confrontation between police and opponents of the Sivens dam project in the Tarn region who say it will destroy biodiversity.

Initial investigations showed traces of TNT on Mr Fraisse’s clothes and skin, suggesting that he might well have been killed by a police stun grenade.

Interior Minister Bernard Cazeneuve has come under heavy criticism over the incident and has since banned the use of the grenades, which are supposedly designed to stun rather than kill.

But Mr Fraisse’s death has sparked a wave of protests calling on the government to apologise for the young man’s death and condemn police brutality.

At least 69 rallies have been held in Paris and smaller towns such as La Rochelle.

Over 1,000 protesters marched in Toulouse and 1,500 in the western city of Nantes at the weekend, where 14 were also arrested.

Bordeaux also saw a substantial protest and marchers in 20 cities across France participated in weekend actions.

Mr Fraisse’s death has further soured relations between President Francois Hollande’s Socialist government and the Greens.

The Green Party, which left the government in April and is now openly hostile to its policies, has been critical of the police presence at the Sivens dam site.

It also said that the government reacted dishonestly to the death and have accused Mr Cazeneuve of initially hiding the truth.

Mr Fraisse was the first person to be killed during a protest in mainland France since 1986.

Demonstrations against the planned dam were part of a growing sequence of environmental protests at infrastructure projects.