Radio France Internationale (RFI) says its correspondent in Cameroon, Ahmed Abba, has been sentenced to 10 years in prison by a military tribunal.
He had been convicted of non-denunciation of terrorism and laundering of the proceeds of terrorist acts.
Campaign groups say Mr Abba was simply reporting on the Islamist militant group Boko Haram.
The Committee to Protect Journalists (CPJ) says the sentence is a travesty of justice.
RFI says Mr Abba, who has always insisted he is innocent, will appeal.
He has already been in jail for almost two years.
Source:BBC