Airbnb filed a formal complaint Monday with New York state's ethics panel against a hotel industry-backed group for failing to disclose lobbying activity.

Meanwhile, a tenant advocate who is a member of the group fired back with his own complaint with the ethics panel against the online home-sharing service.

The complaint by Airbnb Inc. against Share Better—a campaign backed by the hotel industry, the New York Hotel Trades Council, housing advocates and lawmakers—alleges the group failed to register as a lobbyist, failed to disclose how it is funded and failed to report lobbying expenses or file the necessary lobbying reports.