The "politique des auteurs" is a fancy way of saying that some people believe that the director of a movie or the author of a book is a really important part of how good the final product is.
Here's an example: Let's say you're making a cake. Some people might say that the most important thing is the recipe you use or the ingredients you put in. But others might say that the most important thing is the person who actually mixes the batter and puts it in the oven. The "politique des auteurs" people are like those second people. They think that the director or author is the most important part of making a movie or a book.
Why do they think this? Well, they believe that each director or author has their own unique style or vision. That means that no two movies or books are exactly alike, even if they're about the same topic. If you really like a certain director or author, you might want to see or read everything they've ever made, because you know it'll have that same style or vision you love.
So if you're a "politique des auteurs" person, you're always looking for the director or author's name when you're deciding what movie or book to watch or read. You might even care more about who made it than what it's actually about!