Inside New York’s majestic City Hall, the first-floor rotunda has served as a Switzerland of sorts — neutral ground amid the perennial battles between the mayor’s office and the City Council, which share the building.

But on Tuesday, the office of Mayor Eric Adams made an incursion.

As the Council speaker was about to begin a news conference with faith leaders on a matter upsetting to the mayor, his deputy chief of staff suddenly appeared in the rotunda, along with an aide wheeling a hand truck.

Menashe Shapiro, the deputy chief of staff, ordered several reporters seated there for the news conference to stand. He was taking their chairs away.

To close observers of the administration, Mr. Shapiro’s actions seemed familiar, an outgrowth of how the mayor treats people or things he does not like. In this case, it was the subject of the news conference: the Council speaker, Adrienne Adams, announcing her intention to override the mayor’s veto of two criminal justice bills that he asserts would jeopardize public safety if they became law.

Earlier this week, the mayor’s schools chancellor, David C. Banks, did not invite certain major publications to an important speech of his on antisemitism and Islamophobia in schools, purportedly because of space constraints.

Earlier this month, the mayor’s Police Department ejected reporters from their own storied press room at Police Headquarters, relocating them to a trailer outside. Reporters from major media outlets covering City Hall have also been warned that some desks in Room 9, the communal press room, may be taken away.

Now they were coming for the chairs.

If the “City Council wants to give you something to sit on,” Mr. Shapiro said on Tuesday, it was the Council’s job to do so. “Let’s go,” he said.

The reporters did not budge. The standoff was captured in videos by reporters watching the unusual event. Mr. Shapiro eventually gave up, and the chairs were allowed to remain.

The news conference then proceeded, but in suboptimal conditions: The mayor’s office had refused to turn on the big lights that typically illuminate news conferences on the picturesque cantilevered stairs beneath the rotunda’s dome.

A few minutes later, at the mayor’s weekly question-and-answer session with City Hall reporters, Mr. Adams defended Mr. Shapiro’s actions as stemming from a natural desire to preserve order. He declined to say if Mr. Shapiro was acting at his behest.

“We want to maintain control in the rotunda area,” Mr. Adams said, adding that his team would sit down with the speaker’s team to make sure they can “be good tenants together.”

It all struck one longtime Democratic strategist as small.

“Don’t major in the minors,” said Peter Kauffmann, a former adviser to Hillary Clinton and Andrew Cuomo, and a senior adviser to Mayor Bill de Blasio’s Covid-19 response team. “All this mayor does is focus on trivial things.”

The mayor’s focus also extends to criticism, especially from other elected officials.

At a recent news conference where the mayor decried a bill that would require the Police Department to document more of its interactions with the public, Mr. Adams took direct aim at one of the bill’s sponsors, Jumaane Williams, the city’s public advocate.

The mayor derided Mr. Williams for pushing the bill while living on an army base in Brooklyn.

“He lives in a fort,” the mayor scoffed.

After the darkened City Hall news conference on Tuesday, Mr. Williams struck back.

“The mayor has shown that he doesn’t like folks to disagree with him, he doesn’t like transparency, he doesn’t like to shine light on things,” Mr. Williams said. “This very much tracks with the way he is trying to govern.”

Former City Hall communications aides say the rotunda in City Hall is typically neutral ground, available for use by both the mayor’s office and the City Council. The Department of Citywide Administrative Services manages the lights and chairs.

A Council spokesman said that the department’s staff members had declined to turn on the lights. A spokeswoman for the agency had no immediate response when asked why.

“The Council respects the role of a free press and the right to freedom of speech and doesn’t need to try censoring those simply telling the truth,” said Mara Davis, a Council spokeswoman. “We are baffled by the efforts of Mayor Adams’s administration to try muzzling the voices of faith leaders supporting the police transparency advanced by the How Many Stops Act at City Hall today.”

On Tuesday, following the chair contretemps, a reporter asked Mr. Adams if he considered the City Council a coequal branch of government.

“We’re all colleagues,” the mayor said.