Prosecutors in Fulton County, GA say they will not pursue a criminal case against Brittany Marie Lucio because she's completed all requirements of a pretrial intervention program. We're told the program included taking a class about civics and citizen's rights.

Brittany had initially been charged with 1 count of misdemeanor criminal trespass and 1 count of misdemeanor willful obstruction of a law enforcement officer when she was busted in Atlanta a year ago.

Cops said she and her friends ignored multiple requests to leave a Houston's restroom. One of Brittany's friends, Asia'h Epperson, refuted that account ... saying Houston's staffer gladly let them use the restroom and never asked them to leave prior to things turning violent.

Asia'h recorded the incident, which shows a security guard -- an off-duty ATL police officer -- dragging Brittany and her friends outta the joint. When the video surfaced, T.I. got involved and called for a Houston's boycott. He also posted pics showing Brittany's alleged injuries.

Brittany said the off-duty cop used excessive force and said there's zero doubt her skin color played a role in the aggressive way she was taken down. Brittany's attorney, Gerald Griggs, tells TMZ she now plans to sue.

Griggs says, "Ms. Lucio’s name has been cleared and she looks forward to pursuing a civil action against law enforcement for the damage and injuries she sustained. She would like to thank all of her supporters in this matter including [T.I.] and others that stood up for her."