9:56 AM PT -- The Osundairo brothers' attorney, Gloria Schmidt, tells TMZ ... "This is just another sad attempt by Jussie Smollett to try and falsely smear the Osundario brothers, the City of Chicago and the Chicago Police Department. There is no legal merit to his claims, and could be sanctionable."
Schmidt adds, "The brothers were open and honest with the Chicago Police Department, testified under oath in front of a Grand Jury, and stand ready to do so again, in open court, if and when called upon to do so."
Jussie Smolletthas taken the offensive ... he's now suing the City of Chicago, claiming officials created a narrative that he was the mastermind of a hoax attack, and that has cost him dearly.
In the lawsuit, obtained by TMZ, Smollett notes the Osundairo brothers were held for 47 hours and they adamantly denied any involvement in the assault. He says it was only after they were assured they'd get immunity that they started spinning the tale of a fake attack on the streets of Chicago.