Two brothers who were stopped and searched after they bumped fists in the street to say hello to each other, are suing the Metropolitan Police.
Dijon Joseph, 30, and his brother Liam, 29, who are black, said they were wrongly targeted because of their race.
The brothers told the Guardian that they have been stopped and searched by police more than 25 times.
The brother's case was one of five cited by the police watchdog in its review.
IOPC London regional director Sal Naseem said the review revealed "a lack of understanding from officers about why their actions were perceived to be discriminatory".
The Joseph brothers were stopped and searched in February, 2018 outside a restaurant in Deptford high street in south London.
"I was ordering food and I stepped outside. I saw my little brother and that is when we fist bumped," Dijon told the Guardian.
“They surrounded us, physically detained us including by using handcuffs, and searched us in public over a period of about 20 minutes.
"It was humiliating; we were distressed and confused, but that understandable reaction was described by police as ‘incredibly evasive and aggressive’.”
Liam added: "Our very skin colour is ‘suspicious’, which is why we are nine times more likely to be stopped and searched.”
Dijon and Liam complained to the IOPC, which concluded that there was insufficient evidence to uphold a misconduct complaint against the officers.
The brothers then decided to start civil proceedings at court against the Met for discrimination, assault and false imprisonment.
Their solicitor Carolynn Gallwey, from the Bhatt Murphy firm, said: “My firm is receiving a record number of inquiries about the discriminatory use of stop and search at the moment – proper reform has never been needed more”.
Scotland Yard has been contacted for comment.