In two interviews with Empire Online, Katie Leung and Clémence Poésy both talk about Harry Potter and the Goblet of Fire, the books, their characters, fellow actors and in Clémence's case the tasks.
Empire: Cho Chang is quite a complicated girl. How would you describe her?
Katie: Yeah definitely, she has a complicated time. She’s Harry’s crush, but she’s also got a boyfriend in the film so nothing can happen between her and Harry. Basically all that’s involved between Harry and Cho is teasing and a lot of flirting. She’s not an unfaithful person in character; she wouldn’t cheat on her boyfriend or anything.
Empire: I gather that your character is a bit haughty.
Clémence: You mean she’s a bit snobby?
Clémence: She’s a bit cold. She’s the kind of girl I used to hate when I was in high school! She always has tons of people behind her, doing everything perfectly, which is impossible. I talked about it with Mike and said "Do you want it to be snobby?" and he was like "Oh, you know…" and I said, "She’s French right?" and he said “Yeah, exactly!" Mike has got a great sense of humour and that’s what’s in the book; she’s a bit of an image people might have about French girls!