Delivering guilty verdicts on all but three of the 27 defendants, the judge sentenced eight to between three and 10 years in prison with hard labour. He sentenced 16 in their absence to life imprisonment with hard labour and aquitted the other three.
The alleged ringleader, Pascal Tawes, was among the absentees. He is thought to have found shelter in neighbouring Togo from where he telephoned foreign media to proclaim his innocence.
The best-known defendant - sentenced to 10 years with hard labour - was Fousseni Gomina, head of military intelligence under the Marxist president Mathieu Kerekou.