Trump’s gilt palace overlooking Central Park and his golf resorts and solid gold shoes and all the rest of it comes out of the wallets of poor people. That tax scam meant fraudulently hiked rents.

They were collateral damage as Donald J. Trump and his siblings dodged inheritance taxes and gained control of their father’s fortune: thousands of renters in an empire of unassuming red-brick buildings scattered across Brooklyn, Queens and Staten Island.

Those buildings have been home to generations of strivers, municipal workers and newly arrived immigrants. When their regulated rents started rising more quickly in the 1990s, many tenants had no idea why. Some heard that the Trump family had spent millions on building improvements, but they remained suspicious.

That’s how it’s done: you claim fake improvements and then you get to hike the rent.

As it turned out, a hidden scam lurked behind the mysterious increases. In October, a New York Times investigation into the origins of Mr. Trump’s wealth revealed, among its findings, that the future president and his siblings set up a phony business to pad the cost of nearly everything their father, the legendary builder Fred C. Trump, purchased for his buildings. The Trump children split that extra money.

Padding the invoices had a secondary benefit for the Trumps, allowing them to inflate rent increases on their father’s rent-regulated apartments.

Steal from the poor to give to the rich, that’s our boy.

Lawyers who specialize in representing tenants say the Trumps’ current and former tenants may have an opening to challenge the decades-old increases, potentially rolling back rents and collecting damages.

Michael Grinthal, supervising lawyer with the Community Development Project at the Urban Justice Center, a nonprofit legal services and advocacy group, said that the current owners would be held responsible for any damages, but that those owners could have a claim against the president and his siblings.

“If I was talking to those tenants right now, I’d say: ‘Do it. Go,’” Mr. Grinthal said. “This case should be fought.”

Regulations generally allow tenants to challenge rent for the past four years. But the state’s highest court has held that tenants can look back further to show their landlord increased rent through fraud (though damages are still limited).

“If they are making false statements about how much it costs, that would be pretty much dead center of the definition of fraud,” Mr. Grinthal said.

What was that about a “RAT” again?