Brokers warned that the new rules would simply increase what tenants pay in monthly rent, since many landlords will likely pass on the cost of a broker’s fee to their residents in higher rent.

“What was the intended purpose of this?” said Jared Antin, director of sales at Elegran. “If it’s to minimize the cost to the tenant, it just changes when the cost is due. Instead of upfront, they will pay it monthly.”

But state laws limit how much rents can be raised in New York City’s roughly 1 million rent-regulated apartments. There are more than 900,000 market-rate apartments that are not regulated.

Tenant advocates cheered the new broker fee rule, saying it helps tilt an uneven real estate playing field.

“These are important tenant protections and it’s about time we had them,” said Michael McKee, treasurer of the Tenants PAC. “Real estate brokers have been able to get away with a lot for a long time so it’s about time they got reined in.”

Newcomers to New York City have long been mystified and frustrated about having to pay a broker’s fee even when they found an apartment online. But unlike most cities in the United States, landlords often choose not to work directly with renters or market their units on their own. Instead, they hire a broker.

For months, real estate insiders had privately feared this particular interpretation of the new rent laws, which emboldened Democratic lawmakers passed last year after regaining control of the Legislature for the first time in a decade.