MIAMI, Fla. — Mayor Bill de Blasio brought up a controversial talk he had with his biracial son, Dante, in his answer to a question at the Democratic debate in Miami on Wednesday night — one that once damaged his relationship with the NYPD.

De Blasio recalled a conversation about how young black men should act around police officers to prevent being the target of violence.

“For the last 21 years I’ve been raising a black son in America,” de Blasio said.

“And I’ve had to have very, very serious talks with my son, Dante, about how to protect himself in the streets of our city . . . including the fact that he has to take special caution because there have been too many tragedies between young men and our police.”

The issue rankled law enforcement in 2014 when de Blasio revealed the conversation he had with his son after the death of Eric Garner at the hands of an NYPD officer.

“What parents have done for decades who have children of color, especially young men of color, is train them to be very careful when they have a connection with a police officer, when they have an encounter with a police officer,” the mayor said on ABC’s “This Week” at the time.

“It’s different for a white child. That’s just the reality in this country.”

In return, police officers turned their back on de Blasio in December 2014 when he showed up at Woodhull Hospital, where two officers had been pronounced dead just hours earlier.

One Queens cop seethed Wednesday night that de Blasio was reintroducing the controversial topic to get traction in his campaign.

“It’s ridiculous for him to bring that up during a debate,” the cop said. “He is . . . inciting people.”

De Blasio was unapologetic when asked about the controversy while speaking to reporters after the debate.

“Look I’ve been down this road before and it’s the truth — I said it because it’s the truth,” he said.

“You know Chirlane [McCray] and I had these conversations with Dante to protect him and millions and millions of American parents have had the same conversation and somehow it’s not supposed to be part of our American dialogue but it’s the truth.”