Religious education in Rheinland-Pfalz is a regular subject at all public schools. Every pupil who visits a public school is obliged to participate in the religious instruction of his confession.
Parents decide on their children's participation in religious education. After reaching the age of 14, the pupils themselves decide to participate. Pupils who do not attend religious education have to attend Ethics as mandatory subject (§ 40 School regulations for public secondary schools plus, integrated comprehensive schools, high schools, colleges and evening gymnasiums). https://religion.bildung-rp.de/rechtliche-grundlagen/des-religionsunterrichts.html