Actually in 1942 many of the Jews were already being brought to concentration camps
Work or die. No unauthorized talking. No eating meat. No personal possessions. No complaining. No hesitating to follow orders. No religious services or ceremonies.
Concentration camps aren't subject to the usual rules and regulations for prisons and are outside the law. This nearly always means that penalties in camps are much harsher than would be permitted in a prison in the same country. The guards are not held to account for excesses. It also usually means that deaths in camps aren't investigated seriously - or at all. Moreover, concentration camps are usually for people who have not been sent there by a court. In other words, they are sent there without due process, simply on the orders of the government. For example, in Nazi Germany homosexuals who were tried and convicted of homosexual acts by ordinary courts were generally sent to prison; but in cases where the 'evidence' consisted of rumours and hearsay - against whom they was little or no solid evidence - were sent to concentration camps.
After the Geneva Convention where they made the rules of war
Yes, it was another way to assert dominance over the prisoners, there were many rules about the use of them and there were severe punishments for prisoners without a hat. Prisoners would hold their hats tightly when asleep as not to lose them.
Treason, homosexuality, moneylaundering, fraternizing with enemy,
there were many standing rules, including behaviour at roll-call, having to take one's hat off when being addressed by a German, always having a hat. But the main rule would be to do as one was told.
Actually in 1942 many of the Jews were already being brought to concentration camps
In the Nazi death camps or if one chooses to use the term concentration camp, that fits too. The estimated number of exterminated civilians is approximately 6 million. Most of the victims were Jews, however, gypsies, mentally ill people, and political enemies of the Nazi's can be included in the 6 million deaths number. This does not refer to POW camps. There the German Army ran most of them and most POW's were treated according to Geneva Convention rules.
Work or die. No unauthorized talking. No eating meat. No personal possessions. No complaining. No hesitating to follow orders. No religious services or ceremonies.
Concentration camps aren't subject to the usual rules and regulations for prisons and are outside the law. This nearly always means that penalties in camps are much harsher than would be permitted in a prison in the same country. The guards are not held to account for excesses. It also usually means that deaths in camps aren't investigated seriously - or at all. Moreover, concentration camps are usually for people who have not been sent there by a court. In other words, they are sent there without due process, simply on the orders of the government. For example, in Nazi Germany homosexuals who were tried and convicted of homosexual acts by ordinary courts were generally sent to prison; but in cases where the 'evidence' consisted of rumours and hearsay - against whom they was little or no solid evidence - were sent to concentration camps.
In World War 2 war crimes would be most recognized as the German P.O.W camps. In the camps the P.O.W's were treated like the Jews in the concentration camp. The Germans almost completely disregarded the rules of the Geneva convention. In the camps the prisoners were subjected to starvation, derived of treatment of battle injuries and disease. While Germany was not the only country to commit war crimes they were definitely the most recognizable for it.
they were tricked into thinking it was going to be nice at the concentration camps so there were really no restrictions.
Rules of sanitation and health
There were thousands of camps all over Germany a long time before they started building the true death camps. If you tap in concentration camps into any web search engine, it will show you a map of the camps. They were not all death camps, but were camps for Germans who were not Nazi's, and were used for, what they called 're-training'. IF you were released, and still able to think or even walk, you made sure you followed the rules and joined the 'Nazi Party' and kept your thoughts, to yourself in future.
After the Geneva Convention where they made the rules of war
Yes, it was another way to assert dominance over the prisoners, there were many rules about the use of them and there were severe punishments for prisoners without a hat. Prisoners would hold their hats tightly when asleep as not to lose them.