I’ve been on-call in 3 past Jobs in Germany, most of it was pretty similar, 1 week per person, 600-800€ per week and some extra pay on incidents. Current job:

1. ~500€ for a week and I get an extra day off after each week on-call, but no extra pay for incidents
2. With the extra day off its really nice. Our team is light on incidents too.
3. Not much past that. The standard German worker protection laws would apply, but pushing those would not help me much and it might not be the best career move.
4. 5 others
5. EU