Speakers at the event also spoke of an incident yesterday in which a black youth was arrested by Gardai in west Dublin.
Mr Nkencho was shot dead by armed Gardai outside his home in Clonee, west Dublin, on December 30 last after he had earlier been involved in a confrontation at a local shop while he was armed with a knife.
His family say he suffered from mental illness and pleaded with Gardai to withdraw after they confronted him in the garden.
An Garda Siochana said Mr Nkencho was fired on after refusing to drop the knife and Gardai felt their safety and the safety of others was under threat.
The Garda Siochana Ombudsman Commission (GSOC) is investigating the circumstances surrounding the shooting.
Today, the group Youth Against Racism and Inequality (YARI) held a protest at the offices of GSOC on Abbey Street in Dublin city and handed in a letter outlining their concerns about alleged racism.
It outlined the results of a survey they carried out which showed that 45 per cent of people from black, Asian, or Traveller backgrounds felt humiliated and 42 per cent felt fearful after their encounters with Gardai.
YARI's survey was prompted by the death of George Nkencho.
"The survey done by YARI among young people shows a stark level of racism in society and in interactions with Gardai. 91pc of people surveyed experienced micro-aggressions regularly, while 29pc of black people experienced physical assaults,” said Myriam Poizat of YARI.
“We had planned to come to GSOC today to present these findings and to argue for a full and independent inquiry into George’s death, with mental health, class, and importantly, racism to be taken into account in the investigation,” she added.
Speakers at the event also spoke of an incident yesterday in which a black youth was arrested by Gardai in west Dublin while his concerned mother tried to protect him.
The boy was later released having been arrested under the public order act.
“YARI has been inspired by the Black Lives Matter movement worldwide and clearly what we saw yesterday and found in our survey confirms the need for such a movement here in Ireland,” said Ms Poizat.
She said the other key findings of the survey of 167 people was that 70pc had experienced verbal assault, 21pc physical assault.
When asked if they were ever stopped by Gardai for no obvious apparent reason 35pc of people of colour or Travellers said they had; 34pc of respondents from a black /African background said they had; and 29pc of respondents of Asian background.
This compared with 19pc of white, settled people in the survey.
The survey said 35pc of respondents who were randomly stopped and searched by the Gardai said it happened more than three times.