Police officials had warned members of the public the protest was unlawful under the latest coronavirus rules.
Officers spoke with protesters and encouraged them to move on due to them flouting national lockdown measures.
But some refused to listen to police – which has led to three people being issued fines and a total of 11 people arrested.
Chief Superintendent Kim Madill, who oversaw the event, said: “Although under normal circumstances we accept and protect people’s right to protest, under current legislation, attending a protest is not considered an exception to leaving your house and is unlawful.
"We advised people not to attend, and although some people listened, a large amount chose to ignore our pleas and put the safety of themselves and others at risk.
"We always seek to speak with the people who are suspected of being in breach of the regulations, but when people are not working with us or listening to our instructions, then we must enforce the rules and arrest people where appropriate.
"We need to keep our communities safe and although the group have mostly now dispersed, we will continue to monitor the area.
"We would like to thank businesses in the city centre that supported today’s operation and the majority of the public, who were not involved in the protest that were complying with Covid regulations."
Officers on routine patrols around Birmingham city centre also issued 25 fixed penalty notices to members of the public failing to follow the rules.
Police officials said a video circulating on social media – which show arrests from the protest – has been reviewed and they are satisfied the officers acted proportionately.