Brown, 23, is said to have partied with a group of girls including Tran and the news caused a blazing row between him and Rihanna, reported TMZ online.
"She can't get it into her head that Chris will never change. She's given him so many chances since he beat her up in 2009 and he still keeps hurting her by partying with girls," a source said.
Rihanna also missed her scheduled stay with her boyfriend in Paris and headed straight for her performance in Manchester.
"Letting Karrueche meet him is yet another blow for Rihanna that will further disgust her fans. They are already raging that she is back with him," the source said.
Brown reportedly tried to make up with Rihanna by getting a T-shirt with their faces printed on the front but his effort went in vain.
Karrueche is said to be planning to fly to Dubai to see Brown when his tour moves to the Emirate.
The news comes soon after 'Umbrella' singer Rihanna got Brown's nickname, 'Breezy', tattooed on her neck.