Ok kiddo, do you remember the bad guys in movies who want to hurt people because they think they're better than others just because of their race or beliefs? Those are kinda like the Nazis. They were a group of people who did really bad things during a time called World War II. They hurt a lot of people and tried to control the world.
After the war was over, people didn't like what the Nazis did and thought they should be punished for their actions. Punishment is like when you get in trouble for doing something bad. So, they made laws to punish the Nazis and also the people who helped them, called Nazi collaborators. These laws were made to make sure that the bad things the Nazis did would never happen again.
The punishment for Nazis and Nazi collaborators was really serious. They had to go to jail or sometimes even face the death penalty. This means they had to be put to death for what they did. It was a way to show that what they did was really bad and it was not ok to hurt people just because of their race or beliefs.
So remember kiddo, it's important to treat everyone with respect and kindness, no matter where they come from or what they believe in. And if someone hurts others just because of those things, it's not ok and they should be punished for it.