The rights of parents cover different areas: They have the right to be informed about the progress of their children and their have to be offers for support if needed. The parents have the right to choose the secondary school for their children, as far as the capacity of the chosen school is there. The parents have the right to participate in the school life. There are explicit forms of organised participation on class and school level.
The parents have the right of free speech concerning school related issues as a group and as an individual. They can apply to the ministry of education, the regional school administration, political parties, the federal parliament or the media. They can participate in the development or the educational process, especially in the organised forms of participation, but also on an individual level. The parents have the right to an individual consultation with the teaching staff.
For further information see http://www.landesrecht-bw.de/jportal/?quelle=jlink&query=SchulG+BW+%C2%A7+55&psml=bsbawueprod.psml&max=true
There is a brochure for the participation of parents in school at http://www.elternstiftung.de/fileadmin/user_upload/Elterninfo_fuer_gewaehlte_Elternvertreter_2017_2018.pdf