New York Mayor Bill de Blasio has banned "poor doors," or separate entrances to be used by lower-income residents of mixed-income buildings.
De Blasio inserted language into a tax program signed into law on June 25 by New York Gov. Andrew Cuomo.
Housing analysts say real estate developers are likely to look for other ways of appealing to market-rate tenants, like the addition of luxury features inside their apartments.
"I think we'll have to wait and see what developers come up with as a way around this system," says Nicholas Bloom, co-editor of "Affordable housing in New York. "Because people who are paying significantly more, are they willing to cross-subsidize people who are paying much, much less?"
Some developers put affordable and market-rate housing in the same complex but in different buildings.
Mark Joseph, a professor at Case Western Reserve University in Cleveland, says if the city's goal is simply more affordable housing then, "If the developer is going to produce those 30 units separately, but do it in a building that is as high quality, and in a thriving, revitalizing neighborhood, that's one question."
But he says if the city's goal is integration across incomes, it helps for people to share a building.
Click the media player above to hear more.