A Paris court has cleared American author Claire Sterling of charges of damaging the memory of Henri Curiel, controversial Egyptian-born leftist who was murdered in 1978, but fined her for the book's treatment of one of his principal assistants.

The split decision, handed down by a three-judge court last week, concerned two suits, one brought by Curiel's widow, Rosette, and brother, Raoul, and the other by his associate, Joyce Blau.

The suits stemmed from the French version of Sterling's book, "The Terror Network," which the Curiel family and Blau said falsely leads readers to the conclusion that Curiel was linked to the Soviet KGB espionage agency and to international terrrorism.

Curiel, an avowed activist for Third World movements, was assassinated on May 4, 1978.

The Washington Post Magazine, on March 15, 1981, published an excerpt from the Sterling book that dealt with Curiel, who headed an organization called Solidarity in the 1960s and 1970s in Paris.

In explaining its ruling, the court noted that the French publishers, J. C. Lattes, had sought to warn readers of the controversy over Curiel in a long footnote that was not included in the original American edition.

The Curiel family lawyer, Leo Matarasso, also noted that the French publishers had amended the original American text to delete the names of other prominent French activists involved in Solidarity.

In rejecting the Curiels' demands for nearly $83,000 in damages, the court accepted Sterling's argument that she was presenting a "hypothesis" rather than outright accusations that Curiel was a conscious or unwitting tool of the KGB and international terrorists.

In ruling in favor of Blau, the court ordered Lattes and Sterling to pay two sets of damages--about $500 in all--and to black out two passages in the book mentioning her. The passages suggested that Blau had studied Kurdish and traveled to Moscow to further Curiel's and the Soviets' ends--which Blau had denied.

The author and publisher also were ordered to pay for publication in two major French newspapers of the court ruling in the Blau case.

In the case brought by the Curiel family, the court ordered the blacking out of one passage in the book and awarded Curiel's widow and brother damages of about $830 stemming from translation errors.

Lawyers for both parties said last week that they were considering appealing the decisions.

In a somewhat similar case last year, an appeals court found in favor of French journalist Georges Suffert, whose article in the weekly magazine Le Point provided much of the information for Sterling's chapter. Suffert had invoked the same "hypothesis" argument that Sterling used in her defense.