Here’s the email that City Hall sa​ys doesn’t exist.

The Post on Tuesday obtained a copy of ​the internal NYPD message outlining plans for cops to “sweep” the homeless people ​out of two Brooklyn subway stations before Mayor Bill de Blasio arrived there Sunday.

The ​smoking-gun ​email, which bears a 10:53 p.m. ​Saturday ​timestamp, says two cops from Brooklyn’s Transit Division 30 would be assigned to the 4th Avenue/9th Street station, with another two assigned to the Jay Street/MetroTech station.

“Once the Mayor arrives at the 4th Avenue station, he will board the N/B [northbound] ‘F’ train to the Jay Street/Metrotech station. TD-30 officers are to escort the Mayor aboard the N/B ‘F’ train from the 4th Avenue station to the Jay Street station,” the email says.

“Before the Mayor arrives at the 4th Avenue station, the officers are to sweep the station for homeless persons as well as the Jay Street station. There will be press at the 4th Avenue station.”

The email, sent by a cop at Transit Bureau headquarters identified only as Police Officer Nandoo, says the plan was approved by Operations Sgt. James Lynch, who received a copy at both his official NYPD email and private Google Gmail accounts.

It was also sent to the official NYPD email addresses “TD30DESK” and “TransitBureauExecutives.”

The email contains an attachment titled “A Message from JOCDESK,” which refers to the Joint Operations Center inside NYPD headquarters at 1 Police Plaza.

The attachment is a copy of de Blasio’s Sunday schedule — including an 11:30 a.m. trip on the F train from the 4th Avenue/9th Street station — prepared by his press office and forwarded from the “Police Desk” at City Hall.

Law enforcement sources initially told The Post about the email on Sunday, with one source saying it was sent “with the expectation that the subway stations would be free and clear of homeless people.”

When asked for comment later that day, de Blasio press secretary Eric Phillips claimed: “These sources are refusing to provide their names because what they are saying is not true.”

On Monday, Phillips insisted on Twitter that he would “admit it” if any homeless people had been given the boot, but said there was “Zero evidence. Evidence of the opposite, in fact.”

When two sources separately read aloud to The Post portions of the email later Monday, another de Blasio spokesman, Austin Finan, repeated the assertion that what the ​unnamed ​sources were “saying is not true.”

​And during a Monday night appearance on the NY1 cable TV channel, de Blasio said he had “no idea if that [Post] report is true,” but took a gratuitous shot at the paper, claiming: “The outlet that ran it is often not factually based.”

On Tuesday night, Phillips challenged the authenticity of the email obtained by The Post while simultaneously raising the possibility it was circulated among a group of cops who never actually followed through on their plan.

“You have an email, purportedly, between some group of officers suggesting an action. There’s zero evidence the action ever took place because it didn’t take place, as we have said all along,” he said.