In Amelie the protaginist is dressed in red and everything around her is green… not always but most of the time. Which says to me that red probably denotes some kind of passion or love. And the grungy green is the things in life that need to be fixed or that she is trying to fix. You can basically see what I’m talking about within the cover of the movie itself
I also think that the repetitive red and green colors are being used to show warmth and cold feelings for the audience to feel the emotions of the film rather than just see it. The colors take the audience for a journey requiring some thinking. I thought it was not only a good film but that it a masterpiece of the use of color.