The Berlin Institute for Participation (bipar) has been publishing the Citizen Participation Course Book since 2015. The new edition from spring 2023 contains an article by Gesine Schwan entitled "Municipal development councils as effective citizen participation in representative democracy".
"Liberal democracies need a participatory expansion, the representative structure and legitimisation of democracy and the citizens are given the opportunity to participate in the an effective say on current and fundamental issues made possible. One promising approach to this is municipal Development councils. How these work is explained in this article both theoretically and practically using the example of the municipal development advisory board of Herne."
The course book Citizen Participation is available from the Berlin Institute for Participation, and you can read Gesine Schwan's contribution at here download.