Officer Brie is a female mouse and a ZPD officer who was cut from Zootopia.
Early in development of the film, Officer Brie was going to be a supporting character. However, she was cut after Judy Hopps replaced Nick Wilde as the protagonist because the filmmakers wanted Judy to be the smallest officer on the force.
Brie bears a striking resemblance to Donna, a character in Zootopia: Crime Files. It's highly possible that Brie was an inspiration for Donna.