The Grand Ayatollah Sistani answered a question about paying reparation for beating children.
Question: A child who is beaten by parents, and slapped, and also pupils who are beaten by their teachers, if the beating reaches the point which reparation must be paid; are the parents and teachers are liable to these children and how they must satisfy them, and what can the teachers do if they lose contact with them and cannot find them until the end of their lives?
The Grand Ayatollah Sistani: Paying Reparation (Diyeh) is Wajib. In the case of father, can be some of the non-maintenance expenses; and in the case of the teacher, they (beaten children) must be found and satisfy them, and if they cannot be found, (teachers) must pay (to poor, to charities by consulting Mojtahid/religious authority) for failure to respect the rights of others.
source : en.shafaqna.com