Baz Luhrmann, together with Craig Pearce, adapted Shakespeare's Romeo and Juliet for that film and famously stayed true to the original dialogue throughout most of the film. That's one of the film's unique features: the surreal combination of the present-day setting with the antiquated dialogue. So, if you pin down any quote from the movie, whether it's about prejudice or not, you're likely to find it (or a similar version of it) in the text of the play as well.
Here are some of the most salient ones:
1. During the opening fight, Tybalt says to Benvolio: "Peace. Peace? I hate the word, As I hate hell, all Montagues, and thee." He means, "Calm down? No way. I hate having to calm down, and I hate everybody in the Montague family, including you." We can see that Tybalt hates that whole family indiscriminately. Even if there's a Montague he hasn't met yet, Tybalt will hate him anyway. This is prejudice in its purest form.
2. The newscaster who announces the upcoming Capulet party says, "If you be not of the house of Montague, come and crush a cup of wine." She means "As long as you're not involved with the Montagues, you're invited." Here she's echoing the same prejudice that Tybalt expressed so clearly to Benvolio.
3. At the party, Tybalt notices that Romeo is there uninvited, and he expresses his rage to his uncle (Capulet). Capulet responds: "Content thee, gentle cuz, content thee. Let him alone; I would not for the wealth of all the town here in my house do him disparagement: Therefore be patient, take no note of him." He means, "Calm down, just leave Romeo alone and ignore him. I would never insult him here in my own house." Capulet is showing a distinct lack of prejudice towards Romeo. Even though Romeo is a Montague, and the Capulets categorically hate all of the Montagues, the senior Capulet has probably never had any contact with Romeo before and assumes he's just a teenager there to have fun.
4. After the party, Juliet talks to herself about Romeo. "Thou art thyself, though not a Montague," she says, meaning that Romeo is his own person and not just the hated label that her family has applied to everyone with that name. Her words show a rejection of the prejudice towards the Montagues that she's grown up with.
In the above examples, we see characters like Tybalt who hold to their preconceived opinions of others, despite having no compelling reasons or experience for having those beliefs, as well as characters like Capulet and Juliet who understand the need for setting such prejudices aside.