On religious holidays, pupils in Nordrhein-Westfalen, who belong to a religious community can, upon request, be freed from teaching (https://www.schulministerium.nrw.de/docs/bp/Schueler/Ferien-Pruefungen/Religioese-Feiertage/index.html and https://www.schulministerium.nrw.de/docs/Recht/Schulrecht/Erlasse/Religioese-Feiertage/15402.pdf).
You can make an application for days of at religious holidays at the head of school, but these should not add up to more than a week per year.