The police issued a letter of objection on Thursday morning where it cited heightened safety concerns after weekends of protests, saying protesters have committed violent acts, including starting fires, throwing petrol bombs, bricks and steel bars, and destroying public property.
The proposed demonstration was close to buildings at high risk, the police said, referring to multiple metro stations in the region, police headquarters in Wan Chai, and government headquarters and Government House in Admiralty.
"After a cautious evaluation, the police have grounds to believe some participants in the public rally and march would deviate from the designated route and violently destroy high-risk buildings," it added in the letter.
The Front has already submitted an application to appeal.
Embattled Chief Executive Carrie Lam's announcement of a full withdrawal of the extradition bill made earlier this month has failed to pacify protesters, who have pressed on with other demands, which include an independent inquiry into police actions during protests and genuine universal suffrage.