WASHINGTON — An apartment management company partly owned by Jared Kushner, the son-in-law of former President Donald J. Trump, has agreed to pay a $3.25 million penalty and make restitution to thousands of tenants who were overcharged fees and subject to leaks, rodents and mold infestations, the Maryland attorney general said on Friday.

Westminster Management, the property management arm of Kushner Companies, and 25 affiliated businesses that owned nearly 9,000 units across the Baltimore area have agreed to settle a 2019 lawsuit over their rental practices. The companies violated consumer protection laws by charging tenants illegal fees and failed to adequately maintain the properties, the lawsuit said.

“This is a case in which landlords deceived and cheated their tenants, and then subjected them to miserable living conditions,” the Maryland attorney general, Brian Frosh, a Democrat, said in a news conference announcing the settlement. “The tenants were not wealthy people. Many struggled to pay the rent, keep food on the table, take care of their kids, keep everybody healthy. And Westminster used its vastly superior economic power to take advantage of them.”

Under the settlement, former and current tenants at 17 properties can file claims to recover a host of fees that Mr. Frosh said the company had improperly charged them. They could also file claims with an outside arbiter, known as a special master, who can return rental payments to tenants if they faced serious maintenance issues.

Mr. Frosh, in the 2019 lawsuit, accused Westminster and affiliated companies of misrepresenting the quality of units and the level of maintenance they would provide, and of also failing to fix unsanitary conditions.

Kushner Companies initially rejected a settlement offer in 2019. An administrative law judge found in 2021 that Westminster’s violations of consumer protection laws were “widespread and numerous.”

In a statement to The Baltimore Banner on Friday, the chief operating officer for Kushner Companies, Peter Febo, said it was “pleased to have settled this litigation with no admission of liability or wrongdoing.”

An investigation of the company by The New York Times and ProPublica in 2017 detailed the abject conditions at Westminster’s dwellings in Baltimore and its litigiousness against tenants. Mr. Kushner stepped down as the company’s chief executive that January, when he became a senior adviser to Mr. Trump, but he retained most of his stake in his family business.

At the news conference on Friday, former tenants described miserable living conditions and neglectful management: repeated failure to address leaks and floods, haphazard fixes, collapsing walls, mold infestations, eviction threats and tales of mice, dead and alive.

“I expected to receive services that we paid for, to be able to provide, at the very least, our kids a safe and healthy home,” one tenant said. “And as a mom, I feel like with Westminster I failed.”