The ASA was alerted to the advert after a viewer complained that it was irresponsible, harmful and offensive for perpetuating negative racial stereotypes about black teenage boys.
TfL told the ASA that both teenagers in the clip intimidated the victim and behaved offensively.
The ASA said the advert depicted a black boy verbally harassing a white girl, and although another white boy appeared in the clip, “the ad did not show him as jointly intimidating the victim” and “the only aggressor in the ad was the black teenage boy”.
The advert was one of three short social media videos taken from a two minute film.
The other versions showed a white male committing a hate crime against a black woman, and a white male committing a hate crime against another white male.
TfL claimed that an average Facebook user would have typically been shown a mixture of the three adverts approximately three times, and estimated that the chance someone was only shown the cut down at the centre of the complaint was about 2%.
However the ASA maintained that viewers may have only seen the advert in isolation.