The Justice Department filed suit yesterday against Cicero, Ill., a working-class suburb of Chicago, charging that the town deliberately has prevented blacks from living there or obtaining municipal jobs.

The lawsuit is one of the strongest civil rights initiatives taken by the Justice Department under the Reagan administration. The department has been accused of failing to enforce the fair housing laws adequately, and the Civil Rights Division has filed only two other housing discrimination cases in the last two years, none against a city.

The suit charges that through its town officials the virtually all-white suburb has "verbally and physically harassed blacks attempting" to move there. It said that harassment has included efforts to "physically remove such blacks from the town."

In addition, Justice has charged that Cicero set up a residency requirement of a year for all new municipal employes, effectively preventing blacks from being hired for municipal jobs.

Gerald Resnick, Cicero's town collector, said in a telephone interview that none of the town's officials would have any comment until they have had a chance to read and analyze the government's filings.

The lawsuit was brought by Assistant Attorney General William Bradford Reynolds, head of the Civil Rights Division, and filed yesterday in U.S. District Court in Chicago. It charges violations of the Fair Housing Act of 1968 and the Civil Rights Act of 1964.

A spokesman for the Justice Department said this was the first suit ever brought by the department that charged both housing and employment discrimination. During the Carter administration, the department filed suit against Yonkers, N.Y., charging discrimination in both housing and the public school system.

Cicero, which borders Chicago's southwest side, has a population of 61,232, with less than 1 percent of that number blacks. Of the more than 3 million people living in Chicago, about 40 percent are black.

Reynolds said the population figures illustrate "the considerable racial separation in residential patterns in the Chicago metropolitan area."

According to the lawsuit, which lists Cicero town President Henry J. Klosak and the Cicero Housing Authority as defendants, "It has been the policy of the defendant town of Cicero to exclude black persons, on account of race, from residing within its limits in any significant numbers.

"Through its officials, the town of Cicero has verbally and physically harassed blacks attempting to migrate to Cicero, including overt actions to physically remove such blacks from the town."

In addition, the lawsuit charges that the town "refused to participate" in a federal assistance program, the Community Development Block Grant Program, because the money would have encouraged blacks to move to Cicero by providing funding for desegregated housing.

Justice asked the court for an order prohibiting the town, its officials and its employes "from interfering with any person seeking to exercise the right to equal housing opportunity, from engaging in any conduct that perpetuates or promotes racial residential segregation, and from maintaining any residency requirement for eligibility for municipal employment."

The suit also asked the court to order Cicero to take whatever steps necessary "to correct the effects of its past unlawful conduct."

The Reagan administration has filed two previous housing discrimination suits. Both are against private apartment owners, one in Boston and the other in Detroit, and in both those cities private discrimination lawsuits already had been filed against those landlords.