Romantic comedy

There's this attractive young woman on TV standing directly in front of a policeman in full riot gear, smiling at him. I've seen this movie before. But here is a concept for a romantic comedy, they meet during a riot, run into one another later, birds of a different feather but attracted to one another, become lovers, and if I were writing it, they would not end up together but each would have transformed the other, so they end up on opposite sides at the next riot.