The first contact for safety issues is the police authority (call number 110). In case of a risk to the child's well-being through neglect or mistreatment the Youth Welfare Office (General Social Service) should be contacted.
Nordrhein-Westfalen
Youth Welfare offices Nordrhein-Westfalen: https://www.kinderinfo.de/jugendaemter/nordrhein-westfalen/
Child protection Nordrhein-Westfalen: http://www.kinderschutz-in-nrw.de/archiv-bisheriger-seiten/kinderschutz-in-nrw.html
Child protection Center: http://www.kinderschutz-in-nrw.de/fuer-fachkraefte/kinderschutz-in-nrw/kinderschutz-zentren.html
Emergency service for children and youngster https://hast-du-stress.de/krisentelefone-regional-beratungsstellen-fuer-kinder-und-jugendliche-in-not/