When the artist Kameelah Janan Rasheed was commissioned to conceive of a project honoring Brooklyn abolitionists, she wanted to turn the idea of a monument on its head. She proposed to reinvent the design of the anticipated Willoughby Square Park in Downtown Brooklyn with pavement engravings and bronze placards, which would offer questions and prompts to highlight the borough’s antislavery movement and its legacy.

But the preservationists and activists who, for 20 years, have pushed the city to honor Brooklyn’s abolitionist roots were displeased with Ms. Rasheed’s designs, complaining they were too abstract at a time when women and people of color are fighting to see themselves figuratively represented in New York’s monuments.

“We are not going to settle for plaques and engravings, which people will walk right past,” said Shawné Lee, whose family helped ignite the neighborhood’s preservation efforts. “I want to see historical figures represented, because these days we need to see people who look like us in the city’s monuments.”

Since at least 2019, Ms. Lee and other activists have proposed a monument including Black women like the educator and abolitionist Sarah J. Garnet and the investigative journalist Ida B. Wells. Ms. Lee is an owner of 227 Duffield Street in Downtown Brooklyn, a house adjacent to the park that historians now believe was part of the Underground Railroad. It is currently under review for landmark status after it was threatened by eminent domain to make room for the 1.15-acre park, whose completion is estimated in 2022. The city’s most recent plans expect that the building will be preserved.

The confrontation played out last week during a meeting of the Public Design Commission, which reviews permanent monuments and works of art on city property. After listening to public comment, the commissioners voted unanimously to table Ms. Rasheed’s proposal, a $689,000 dollar project steered by the Department of Cultural Affairs and the city’s Economic Development Corporation.

“We are not going to give approval until this process has moved further along,” said the commissioner Signe Nielsen at the meeting, adding that a later review would allow “greater opportunity for the artist to hear some of the voices that perhaps have not been heard.”

The meeting was a turbulent introduction for Ms. Rasheed into the city’s public art process, which has become increasingly contentious under Mayor Bill de Blasio, who has commissioned nearly a dozen new monuments in the last two years through a program called She Built NYC.