While reflecting on his 100 days in office last month, Mashaba told the press that illegal immigrants are contributing to criminal elements and should leave the City.
The organisation says it will submit a list of demands to the mayor’s office on Monday, calling on him to apologise for his utterances.
The forum’s Marc Gbaffou says Mashaba’s comments came as a shock to their members.
“We were all shocked to hear that the first citizen of the City of Johannesburg can make these utterances, because with him being the first citizen he would know that Johannesburg is the melting pot of Africa.”
Earlier this month Mashaba said he stands by his statement, adding that rules must be upheld and respected.
The Home Affairs Department then issued a warning to the mayor, saying his comments could be misconstrued and lead to xenophobic violence.
But Mashaba maintained people living in the city should have the necessary documents to prove that they are allowed to be in the country.
Additional reporting by Masego Rahlaga
(Edited by Masechaba Sefularo)