Lawyers for Cameroon’s main opposition leader, Maurice Kamto – who was arrested on Monday, say he has been charged with insurrection.
If found guilty, he could face a prison term of five years to life.
The lawyers say Mr Kamto and 200 other detainees also face seven other charges, including holding illegal gatherings and disturbing the peace.
The Cameroon Renaissance Movement (MRC) party leader was arrested after protests at the weekend that took place in some major cities in Cameroon and at embassies in Paris and Berlin.
Protesters were demonstrating against the result of last October’s election, which they say was rigged.
Mr Kamto came second in the presidential election, which was won by Paul Biya – who has ruled Cameroon for the past 36 years.
Christopher Ndong, Mr Kamto’s lawyer, said his client denied the charges and that his right to the freedom of speech had been infringed.