The Civilian Assembly was a political body in the Cardassian Union. It was a separate entity from the Detapa Council. Members of the military also sat on the council.
In the 2360s, the Brotherhood planned to disrupt the balance between the Civilian Assembly and the Central Command. Elim Garak and Pythas Lok were assigned to find evidence of the Brotherhood's subversive activities that they could present to the Assembly and the Council. Procal Dukat wished to remove the Assembly from power. (DS9 novel: A Stitch in Time)