Denver city officials are investigating after resident Jesse Parris said he was told Monday night that he could not wear a political button into the City and County Building, where the City Council was holding its weekly meeting, he said.

Parris’ button declared: “AMERICA MUST ATONE. BLACK REPARATIONS NOW!” He attended the nearby Bernie Sanders rally instead of removing the pin.

A contract security guard told a reporter that pins were categorized with signs and pieces of paper and other forms of literature, which were recently banned from parts of the building.

A city spokesperson said that the city is looking into the incident, adding that political pins at public meetings are protected speech.

An order signed by judges on July 17 forbids the displaying of “signs or other materials” in certain areas of the City and County Building, which also houses county courts. The order doesn’t apply to non-court parts of the building, such as the council chambers, but there is only one entrance for evening meetings.