Hearings will open today in Cambridge to decide the fate of a proposed Dunkin' Donuts and a $5.8-million parking garage for Harvard Square.

A Middlesex County Superior Court judge is scheduled to consider today whether a Dunkin' Donuts will be allowed to move into 24 Boylston St.

Members of the Harvard Square Development Task Force and Harvard Square businessmen filed suit several months ago against James de Vellis, owner of the proposed franchise, and the Cambridge Board of Zoning Appeals for alleged illegal authorization of the Dunkin' Donuts Harvard Square permit.

The appeal came soon after the zoning board in January gave deVellis permission to move into the Boylston St. location despite strong community objection to the authorization.

The case is expected to center on the validity of the zoning board's 4-1 decision to grant the permit to deVellis, with the plaintiffs contesting that board member Paul A. Gargano, who voted with the majority to grant deVellis the permit, is not a "bona fide" resident of Cambridge.

The plaintiffs charge that because Gargano does not reside in Cambridge the board was improperly constituted to make the decision.

Gargano said yesterday he cannot comment on the case because he is being called as a witness today.

A public hearing on the 600-space parking garage, proposed for the Nutting Rd.-Mt. Auburn St. intersection next to the MBTA subway yards, will take place at 8:30 p.m. in the City Council chambers.

City officials said last week the parking garage may help alleviate some of the parking problems caused by cutbacks in on-street parking.

The parking lot will be constructed with funds raised by a bond issue and revenue available from the city's traffic violation fund, Robert Bowyer, director of planning for the city of Cambridge, said last week. He said real estate taxes would not be affected by funding for the parking lot.

A hearing on a Cambridge sign ordinance law which would ban, over a period of three years, all protruding and flashing signs, will take place Tuesday at 7:30 p.m. at the City Council chamber