Hundreds of people congregated outside the Bullring shopping centre after teenage vlogger Jayden Gray, known by his YouTube name Canking, publicised a meet and greet event from 2pm.
West Midlands Police has now confirmed that three people were arrested - two on suspicion of drugs offences and one for allegedly throwing an egg at an officer.
The force said officers would be speaking with the event organisers, who had encouraged fans to meet in the city centre despite gatherings of more than six people being banned under the coronavirus lockown laws.
Footage taken at the centre showed large crowds of people standing closer than two metres apart and pushing forward to see Canking and other vloggers.
A spokesman for West Midlands Police said: "Three people were arrested during a large gathering of people in Birmingham city centre yesterday organised via social media.
"Crowds started gathering at around 2pm, and there were reports of small pockets of anti-social behaviour and disorder.
"By 8pm, most of the crowd had dispersed.
"One person was arrested for throwing an egg at an officer, a second person was held for a drugs offence, and the third for drugs and public order offences.
"Officers will be making further enquiries with the event organisers."
Canking, who is from the Birmingham area, wrote on his Instagram page yesterday evening: "Thank you to everyone who showed up to the meet and greet! Nuff love to the fans and supporters."
He is known for videos posted on YouTube that show him asking people questions on the street and offering money for "challenges" such as kicking and punching him or singing songs.
Canking has more than 269,000 subscribers to his YouTube channel and almost 50,000 followers on Instagram.
A spokesperson for Bullring & Grand Central, who hadn't been told the event was planned, said: "The safety of our shoppers, colleagues and retailers is our foremost concern and we urge all visitors to follow social distancing guidelines."