Officers were joined by Mayor Lori Lightfoot as well as Bauer's family and friends to memorialize the commander who was shot and killed while attempting to arrest a suspect near the Thompson Center on Feb. 13, 2018.
A bell was rung 29 times in reference to Bauer's star number, and a radio all call paid tribute to the man who served on the force for 32 years before he was killed.
"Two years ago today, the world Grace and I knew came crashing down around us when Paul was killed," said his widow, Erin Bauer. "There are days when it seems like it was just yesterday, that's how fresh the pain still is."
RELATED: CPD commander fatally shot at Thompson Center in Loop ID'd
Bauer was trying to arrest Shomari Legghette, a four-time convicted felon, outside the Thompson Center when he was killed. After Bauer chased him into a stairwell, Legghette opened fire during a struggle.
The vigil comes one day after Erin Bauer filed a lawsuit against Armslist.com, an online gun auction site that sold the weapon police say Legghette used to kill Bauer.
Bauer is accusing the site of selling guns without background checks.
Armslist.com has not yet commented on the lawsuit.
RELATED: CPD Cmdr. Paul Bauer's widow files lawsuit against Arms List gun website
On Thursday, Mayor Lightfoot reflected on the commander's legacy.
"He personified what it meant to be a police officer and he was also a great public servant," Lightfoot said. "Today, Commander Bauer's legacy is carried on by the men and women that he served with who are gathered here today."
Bauer's second in command at the time, Melvin Roman, wore a button on his jacket to honor his boss, calling this a somber day.
"Very emotional but you see the amount of support we have from the officers and the community and it's always phenomenal," said Roman, who's now in charge of the 14th District.
Erin Bauer noted that her husband was never one to want to the spotlight, but she expressed her thanks to all those who gathered to honor him.
Bauer's accused killer goes on trial later this month.