NEW YORK - The debate is evergreen, sprouting every holiday season like mistletoe: What sort of symbols should be placed on public view around Hanukkah and Christmas? But while the arguments normally focus on village greens or courthouse steps, a new lawsuit has opened up another battleground, the New York City schools.

Aided by the Catholic League for Religious and Civil Rights, a Queens family sued the city Monday in U.S. District Court in Brooklyn, alleging that its policy on holiday displays in schools discriminates against Roman Catholics.

The policy permits what it calls secular holiday decorations, including "Christmas trees, menorahs and the star and crescent," according to a memorandum that the schools chancellor's general counsel distributed a year ago. If school officials display one symbol, the memorandum said, they should display those of other "beliefs or customs."

But William Donohue, president of the Catholic League, said the menorah and star and crescent are religious symbols, while the Christmas tree is not.

"I'm offended that we're some sort of second-class religion that would be satisfied with a tree," he said. The school system should allow a Nativity scene or ban all holiday symbols, he added.

The league opposes what it says are biases against Catholics.

The lawsuit accuses the Department of Education of promoting Judaism and Islam, of coercing students to accept those religions and of sending a disapproving message about Christianity. It also names Joel I. Klein, the schools chancellor, and Sonya Lupion, principal of Public School 165, the Edith K. Bergtraum School. It seeks an injunction against the policy.

A spokeswoman for the city's Education Department, Marge Feinberg, said: "We're following the Constitution, and we're adhering to the Supreme Court decision." She declined to comment on the specifics of the case, saying the department had not seen it.

In a 1989 decision involving displays in Pittsburgh, the Supreme Court ruled that a Nativity scene at the Allegheny County courthouse was unconstitutional because it lacked secular symbols of the Christmas season, making it seem as if the county endorsed the religious message. But it said an 18-foot- tall menorah on the steps of City Hall was acceptable because it was coupled with a 45-foot-tall Christmas tree. The ruling essentially said context had to be considered in each case.