The city’s new campaign finance legislation, intended to curtail influence peddling in government, carves out a special exemption for another group besides labor unions — “affordable housing” providers, many of whom get government money.

The legislation, which passed the City Council earlier this week, limits campaign contributions from lobbyists and entities that do business with the city to no more than $400 for a citywide candidate. Tucked into the legalese, however, is a clause that states that “affordable housing” providers are not to be included in that category.

The union exemption, which is more clear-cut, was reported earlier by the Sun and has been the subject of considerable public discussion. The language about “affordable housing” developers, however, has attracted little or no attention. The law hasn’t yet gone into effect, so the significance of the provision is yet to be seen. The Council speaker, Christine Quinn, says there is no exemption, and that the language primarily captures participants in housing programs over which politicians have no discretion aren’t swept up in the contribution restrictions.

Council Member Oliver Koppell, who voted against the bill, said that while most affordable housing providers make positive contributions to the city, they get “enormous public subsidizes” and should not get a special exemption.

“If one looks for people who might be deemed to ‘pay for play’ these would be the very people,” he said. “The building of affordable housing is a competitive business.”

An associate professor of law and real estate at Baruch College, Jay Weiser, said the language in the bill does not specify that the exemption would only apply to affordable housing providers that automatically qualify for certain programs. That, he said, means city officials will have a say.

“It looks like a sophisticated effort by politicians to launder government money and turn it into campaign contributions for themselves,” he said. “It’s all dressed up as the virtuous non-profit affordable housing sector.” But, he noted, it’s a big slice of the economy.

Ms. Quinn said the clause applies mostly to the federal Section 8 voucher program and another program called “80-20,” which gives developers financial benefits for making 20% of their projects affordable.

“You could give me gazillions of dollars and I have no impact on whether you get Section 8,” Ms. Quinn told the Sun.

She also noted that many providers would be captured by other parts of the bill. If, for example, a developer has a land-use application or a zoning request their campaign contributions to candidates would be capped, even if they also provide “affordable” housing.

“If you’re building an eight-story building in a manufacturing zone and we have to change it to residential … you’ve got to come through the City Council so you’re included,” Ms. Quinn said.

The legislation, which runs more than 15,000 words over 16 single-spaced pages, doesn’t clearly indicate how significant or insignificant the clause will be once the law goes into effect.

Real estate operators and observers said that the city does have discretion in some areas over housing geared to low- and middle-income residents. They said, however, that most of the decisions are made by the mayor’s administration rather than the City Council, usually through the Department of Housing Preservation and Development or the Housing Development Corporation, which provides bond financing for multi-family affordable housing projects. The contribution cap applies to mayoral campaigns as well as to Council candidates.

The executive director of the New York State Association for Affordable Housing, Bernard Carr, said that while his organization did not even know about the exemption, he believes it makes sense.

“What affordable housing developers do is not exactly the same as the guy who sells rakes to the Parks Department,” Mr. Carr. He said affordable housing providers are often borrowing money that they pay the government back. “Is that the same as getting a multi-million contract to sell something?”

“If you fit the criteria for a tax-exemption program you get it, if you don’t you don’t get it. It’s not about somebody calling to intercede,” he added.

Mayor Bloomberg and Ms. Quinn have painted the campaign finance legislation as the most comprehensive pay-to-play crackdown in the nation. It’s been largely hailed by good-government groups.

Those defending the “affordable housing” clause said it is aimed at community-based developers. They also noted that in some cases the city requires landlords to take Section 8 and that it would be unfair to subject them to donation restrictions.

The president of the Rent Stabilization Association, which represents landlords, Joseph Strasberg, said that while there was “clearly a conscious decision on the part of the drafters to carve this out,” he does not have a problem with it. He said it is unlike the union exemption, which was purely political.

“The mantra of this administration, the Bloomberg administration, is affordable housing,” he said.

When asked about the affordable housing exemption yesterday, a spokesman for Mr. Bloomberg, Stuart Loeser, said: “The mayor has said several times about this bill that we can’t let the perfect be the enemy of the good.”