An adult black man tells story about running from the n*gger

I am trying to find out the name of a movie where an adult black man talks with another man (can't remember if he is black or white) about when he and his older brother had started at a new school, probably in the 60s. Walking to the school in the morning, some white kids started laughing and running, saying something like "Run, it's a n*gger!" So the boy, not knowing what a n*gger was, started laughing and running with them until his older brother stopped him and told him that the white kids were running from them. I think this conversation starts at the beginning of the movie, but not absolutely sure. Thanks.