Protesters had gathered in Cotonou, Benin’s economic hub, to march against President Patrice Talon but officers moved in when they strayed off an agreed course.
“The police hit honest citizens,” said demonstrator Cyrille Medagbe as some protesters set light to barricades made of tyres in the city centre.
People’s Liberation Party founder Leonce Houngbadji said peaceful marches had been called in Cotonou, in the administrative capital Porto Novo and in three other cities.
“The Benin people are...fed up with the government of Talon and how the country is being run,” he said before the clashes broke out.
Most of the protesters were students, young workers, motorcycle-taxi drivers and market women. Talon, a former businessman who made his fortune in cotton, was elected in April 2016, and has since tried to revamp the West African nation’s stuttering economy.
But his proposals for free-market reform have sparked widespread concern, leading to a series of public sector strikes that have crippled the education, justice and health sector.