A French defense ministry spokesman said yesterday that Soviet and Cuban personnel have been seen inside Zaire assisting rebel forces in the struggle for Zaire's Shaba province.

Pierre Sauliere, the spokesman, said reconnaisance had spotted a column of Cuban and Soviet military advisers within 36 hours preceding the onset of the French rescue operation.He said the Soviet and Cubans were supporting the Katanga rebels and were seen withdrawing from the area, presumably into Angola.

No other French officials made any mention of Soviet and Cuban presence inside Shaba, formerly Katanga.

French television, however, quoted the Belgian consul at Kolwezi as saying that Katangans had started looting, raping and killing after the Soviet and Cubans left.

The government of Zaire has repeatedly asserted that Cubans and Russians were helping the Katangan rebels, but these pronouncements have been viewed as self-serving and designed to encourage Western involvement in the conflict.

A senior Belgian official, asked earlier whether there were any Soviet bloc military personnel in Shaba, quipped, "if there were Cuban troops we would see it a little more clearly."

French President Valery Giscard d'Estaing defended the French action in a nationally televised interview by stressing alarming reports about conditions of some 3,000 Europeans in the Shaba area.

"When the real situation of the civilian population becomes known," he said, "the need for us, our Belgian friends like ourselves, to come to its aid as rapidly as possible will be understood."

Apparently stung by criticism that the real objective of the French was to defeat the rebels and save the government of President Mobutu Sese Seko, Giscard stressed several times that the mission of the French forces was limited and they will be withdrawn as soon as the safety of the Europeans is secured.

The criticism was implicit in a statement by Belgian Premier Leo Tindemans who said, "The nature of the French operation in Zaire is very different from ours. Our objective is purely humanitarian."

There was considerable tension between Paris and Brussels yesterday over the course of the rescue mission. The Belgians have complained that the French had rushed in precipitously without awaiting the outcome of negotiations by the Red Cross and other humanitarian organizations.

The French, in turn, have angrily charged that the Belgians had taken the risk of compromising the entire effort by announcing that it was under way two hours before the first wave of French legionnaires was actually dropped on the Shaba town of Kolwezi.