NEW YORK -- Three years and two months after his wife's vice-presidential nomination thrust him into the public spotlight, John A. Zaccaro goes on trial here today on charges of extorting a $1 million bribe in connection with a Queens cable-television franchise.

The New York real estate broker and husband of former House member Geraldine A. Ferraro (D-N.Y.) is alleged to have conspired with Donald R. Manes, the late Queens borough president, to demand payments from a company bidding for the lucrative franchise.

Zaccaro has said he is "completely innocent" of the charges. Ferraro told local reporters earlier this month that she is "prouder than . . . ever" to be married to Zaccaro but that an atmosphere of "municipal McCarthyism" will make it difficult for him to receive a fair trial in Queens State Supreme Court.

Zaccaro was sentenced to 150 hours of community service in February 1985 after pleading guilty to a misdemeanor charge involving a fraudulent real estate deal. Prosecutors said he had prepared a false sales contract and altered appraisal involving a Queens real estate deal.

At the time, Zaccaro said he hoped that the plea would end "the microscopic attention given to my personal and business affairs."

Last September, however, Zaccaro was ordered to pay about $20,000 to an elderly woman's estate for what a judge called Zaccaro's improprieties in borrowing money from the estate, for which he was a conservator.

The next month, Zaccaro was indicted in the cable-television case. Ferraro said then that her husband would prove his innocence "and maybe once and for all we're going to put an end to the '84 campaign and the nightmare we've been living for the last two years."

Zaccaro's tangled finances created political problems for his wife, after Democratic presidential nominee Walter F. Mondale picked her as his running mate in 1984. The problems intensified after disclosures that Ferraro had a one-third interest in the family-owned real estate company, and that, in her first House race in 1978, Ferraro had received from her husband $130,000 in loans that were later ruled illegal.

The couple's interests apparently have overlapped again in the latest case, and the Queens district attorney has subpoenaed Ferraro's appointment records, telephone logs and other information for much of the time she was in Congress.

The indictment charges that, in 1981, Zaccaro sought a payoff from an attorney for Cablevision Systems Corp., the state's largest cable operator, by promising that Manes would secure the Queens franchise for the company. Zaccaro also suggested that Manes would make sure that the firm did not win the franchise if the money was not paid, according to the indictment.

Cablevision refused to make payments and did not receive the award. Manes committed suicide last year after prosecutors began investigating his role in another bribery scheme.

Two associates of Zaccaro and Manes have been convicted.

Francis X. Smith, former chief administrative judge of Queens State Supreme Court, was sentenced this month to a year in prison for lying to a grand jury about his role in the cable television scheme. Consultant Michael A. Nussbaum was convicted last month of soliciting a bribe for Manes in connection with the franchise.