Interestingly, the Pele Yoetz writes that not only is it forbidden for someone to hit his child, but it's also forbidden to hit someone else. In other words, hitting a child is even worse than hitting another man.
When parents or a teacher are forced to punish a child, they are not allowed to hit the child on his head or eyes, only to lightly slap the child on his legs.
Any other person, but a parent or teacher is forbidden to even slightly hit a child. In fact, Beth Din can force someone to pay restitution to a child for slapping him.
Pele Yoetz is a book of Jewish Musar literature (Ethics) which gained immediate popularity when it was first published in Constantinople in 1824 by Rabbi Eliezer Papo (1785–1828).
Read more in EnglishPele Yoetz (Chapter 5): Our Sages said, One who hits his grown son is liable to nidoi (ostracizing). They explain that it is likely to result in rebellion, cursing and physical attack against the father and thus the father transgresses the prohibition of placing a stumbling block before the blind. Thus it is clear that it is not just his grown son that he should not hit. Rather the warning is against hitting even a young child. This applies then to anyone he knows will not accept his authority for example in our times when chutzpah is common and a son rebels against his father. Thus he should not only avoiding hitting but even angrily chastising someone – results in an angry response and refusal to listen to criticism.
Read the Pele Yoetz in Hebrew