Bill Condon gave an interview to The Movie Times about 'Beauty and the Beast' and talked about Emma at 2:25.
Here's a transcript. Credit Watsonuncensored if you use it.
"How do you distinguish Belle again 25 years later in a live-action way? I think that was so much a part of the casting of Emma Watson. Because I do think of all the actresses her age, of her generation, she is the one who's sort of most closely defined with women's issues. Her activism with the UN... But in general it's really become her life's mission. So it was very exciting. I remember writing her a note and kind of pointing out that choices that people, actors making their careers sort of become part of their own autobiography, and that seems to have such a great fit in her life that I was hoping she was interested. Turned out she had been interested for years, have been developing her own version of it and what was then so exciting when she got on board was to work together with her."