In Bremen, general public schools in primary and lower secondary education give religious lessons independent of religious denominations (§ 7 Bremisches Schulgesetz). The religious education is a mandatory subject with transfer-relevant grading and obligatory for all pupils. It is given by teachers of religion. However, according to Article 7 (2) of the Basic Law (fundamental right to freedom of religion), legal guardians have the right to unsubscribe their child from religious instruction. Those students who are unsubscribed from religious education have to participate instructions in an alternative subject, for example in philosophy.
Education Plan Religion in Bremen: https://www.lis.bremen.de/schulqualitaet/curriculumentwicklung/bildungsplaene-15219