Once upon a time, a long time ago, in a country called France, there were some people who were followers of a religion called Judaism. These people had been living in France for a very long time, even longer than some other people who were there. But some other people didn't always like the Jewish people and treated them badly.
Then, one day, the leaders of France made a special rule called "décret Crémieux." This rule said that all the Jewish people who lived in France would be considered just like all the other people who lived there. They could have the same jobs, go to school with everyone else, and do all the same things.
This rule was really important because before it, Jewish people were not allowed to be French citizens. They couldn't join the army or hold certain kinds of jobs. But with this new rule, they were allowed to be French citizens just like everyone else.
Some people were happy about this rule. They thought it was only fair that everyone have the same rights. But some other people were not happy. They didn't like Jewish people and thought they should be treated differently.
So, even though it was a really important rule, some people didn't want to follow it. But eventually, more and more people realized that treating everyone the same was the best thing to do. And that is how the décret Crémieux helped Jewish people in France be treated more fairly.