The city's Office of Human Rights has found what it describes as "reason to believe" that former corporation counsel John R. Risher Jr. discriminated against black in hiring, job assignments and condition of employment, OHR director James W. Baldwin said yesterday.

Baldwin said his office made a "probable cause finding" of discrimination by Risher in those three areas but did not find evidence that he discriminated against women or in the office's overall promotion process.

Calvin Rolark, a black newspaper publisher, filed a complaint last year with the human rights office charging discrimination by Risher against blacks and women in hiring, job assignments and promotions, "the whole works," Baldwin said.

Rolark's complaint was filed a month after The Washington Post disclosed that the number of blacks who were assistants to the corporation counsel dropped during Risher's first year in office.

Risher, in a long and detailed report to Baldin earlier this year, denied the charges. Figures in his report showed that four of the five black attorneys named assistant corporation counsels between June 1976 and December 1977 were appointed within the three months following the filing of Rolark's complaint. Three of the four were black women, the report said.

Risher resigned as corporation counsel in June, saying he did not want his actions as the city's chief lawyer to be clouded by the political overtones of the reelection campaign of his boss and friend, Mayor Walter Washington.

Acting Corporation Counsel Louis P. Robbins could not be reached for comment yesterday.

Baldwin said yesterday that he could not comment on "the merits of the case" against Risher's office. "The next step is to attempt reconciliation in accordance with the District's affirmative action plans," he said.

If that doesn't work, Baldwin said, public hearings airing the charges and the findings of the human rights office will be held.