A man purporting to be a police officer ordered a newsstand in the Square to stop selling The Realist magazine Saturday.

Philip Nini, proprietor of Nini's Corner at Massachusetts Ave. and Brattle St., said the man bought a copy of The Realist Saturday morning. He reappeared in the afternoon, showed Nini a badge, and ordered him to stop selling copies of the magazine, "because it was obscene," Nini said.

Both Cambridge and Boston police authorities denied any knowledge of the incident.

The Realist styles itself "the fire hydrant of the underdog," and runs satiric articles on current affairs. The issue in question contained an article by George Lincoln Rockwell, commander of the American Nazi Party, a number of jokes and cartoons, many directed against Roman Catholics, and some off-color humor.

Paul Kressner, editor of the magazine, denied that it was obscene and said he had never had any difficulties with censorship before. The Realist, published monthly in Greenwich Village, has a circulation.