A group of New York City tenants has sued the Kushner Companies, the family real estate firm of Jared Kushner, President Trump’s son-in-law and White House adviser, accusing the company of systematically violating the state’s rent regulations.

Claims could grow to more than $1 million in rent overcharges in a single apartment building if the company is found liable.

The lawsuit, filed in the New York State Supreme Court in Brooklyn on Tuesday, was on behalf of nine tenants, but it concludes that more than 100 former and current tenants could have similar claims. The complaint is seeking class-action status.

The nonprofit group that researched the building, Housing Rights Initiative, said it had found similar irregularities in more than 50 other Kushner Companies apartment buildings across New York City and is studying potential future litigation related to those properties.