Foes of the home-sharing website Airbnb kicked off a $3 million publicity campaign Friday to curb the spread of what they charged was a business model predicated on lawbreaking.

The campaign, funded largely by the hotel industry and hotel unions, calls on Mayor Bill de Blasio's special investigative unit to go after Airbnb, said politicians and housing activists at a City Hall rally. Airbnb pairs residence owners and legal tenants with short-term renters seeking an alternative to hotels.

Chanting "Hey-Hey! Ho-Ho, Airbnb has got to go!" and waving homemade signs like one reading "Homes Not Hotels," speakers said renting apartments meant for permanent residents to tourists ruins neighborhoods, breaks zoning laws and depletes already scarce affordable housing.

"Those folks are making money at the expense of the law-abiding residents of that building. When people rent out apartments as illegal hotels, it makes life a nightmare for the neighbors in the building who've got tourists coming and going at all hours of the day and night," said Assemb. Richard N. Gottfried (D-Manhattan), a co-author of a 2010 law restricting short-term rentals of residential properties.

The coalition has hired the consulting firm Metropolitan Public Strategies, whose operatives staffed the City Hall rally. Nearby were their counterparts from Airbnb, who offered the company's response. A spokesman would not say how much Airbnb spends on its lobbying and marketing.

Airbnb says many of its hosts use the rental cash to help make ends meet and disputes one of the protesters' main arguments: that based on a data analysis of listings, nearly two-thirds of apartments on Airbnb as of January were for an entire apartment, in violation of state law.

Airbnb counters that "87 percent of Airbnb hosts share the home in which they live," although the company could not immediately provide the study's methodology.

Over the past few months, advertising for Airbnb has blanketed television and mass transit, showing happy-looking families dining with their guests.

Asked Friday about the anti-Airbnb protesters' demands, de Blasio said at an unrelated news conference that the city would crack down on lawbreaking apartment rentals "very aggressively."

"We have been increasing enforcement, and you'll see more enforcement as we go along," de Blasio said.

Airbnb has hired de Blasio's former campaign manager, Bill Hyers, as a consultant. The mayor said that would have no effect on the administration's decision making.