France and the United States, with different national constraints on their actions, have agreed to help African nations defend themselves against "destabilizing external forces" if those nations will put together "some operative arrangement," French Foreign minister Louis de Guiringaud said yesterday.

That was agreed upon by Presidents Carter and Valery Giscard d'Estaing in their White House dinner meeting Friday night, Guiringaud confirmed in an interview with The Washington Post. Soviet-Cuban actions in Africa, he said, are producing "destabilizing tensions" across the continent.

"Both presidents referred it to their foreign ministers," Guiringaud said, "and I discussed it this (Monday) morning with Cy Vance."

Guiringaud and French Ambassador Francois de Laboulaye met for an hour with Secretary of State Cyrus R. Vance at the State Department yesterday morning. They had opportunuty to pursue the discussion last night at a dinner of the foreign ministers of the Big Four (United States, France, Britain, West Germany) preceding this morning of the 15-nation north Atlantic Treaty organization summit conference. The conference will be formally opened by President Carter.

France has already shown its "willingness to back those African states who are willing to defend themselves," Guiringaud said, especially referring to the parachute drop by French Legionnaires on the beseiged copper-mining center of Kolwezi, in Zaire's Shaba Province.

"And the president (carter)," he said, "has shown a willingness to do the same - as much as present congressional legislation permits. He also has indicated his intention to get from Congress more flexibility."

In an interview at the residence of the French ambassador, on Kalorama Road, Guiringaud said that during the last two years "we see Cuban forces - regular forces - and large bodies of Soviet military advisers, active in Africa - in Angola, in the Horn of Africa, in Mozambique, and we see the hand of the Cubans in many of the destabilizing tensions which we have to face in Africa."

There are enough "local causes of tension" in Africa, largely due to the 19th century national borders that cut across tribal lines, Guiringaud said, "but tension would not develop into open conflict without the help of the Soviet-Cuban intervention."

But in order to try to checkmate that intervention on any regular basis, the French career diplomat said, "We first have to see what the African states can do, and will do."

"We are not defending in Africa a regime, or a man, anywhere," he said. "We are trying to help this continent maintain stability," because the resources and attention "spent on prevention of destabilizing are lost to development, and we think Africa has better things to do than to fight. . . ."

At a summit conference in Versailles early last week of 21 African nations attended by Zaire President Mobutu Sese Seko who appealed for help for his invaded province, a pan-African anti-aggression defense force was discussed.

Gabon's President Omar Bongo, currently head of the Organization of Africa Unity, proposed the joint African force. The Ivory Coast's Felix Houphouet-Boigny, dean of African leaders, said "we count on the support of France" to honor its traditions and its commitments . . . to come to our aid if we are attacked."

In Versailles, the West African Economic Community, which consists of the Ivory Coast, Senegal, Mali, Mauretania, Niger Upper Volta, considered transforming itself into and expanded defense alliance. Togo is an associate member of the present community. Bongo said an African defense pact might also include Gabon, the Central African Empire, Chad, Cameroon, Zaire, Rwanda and Burundi.

Morocco's King Hassan II, who sent Morrocan troops into Zaire in 1977, in the first cross-border attack by ex-Katanga gendarmes from Angola into Shaba Province told The Washington Post last week in an interview in Fez, Morocco, that he will send troops to help restore order there again only other African nations contribute troops. "I will not go there alone again," he said.

Guiringdud's comments yesterday showed that President Carter discussed with France's president the limitations on what the United States might contribute to support a pan-African force. Guiringaud said that during the three-hour dinner at the White House, a third of the time, one hour, was spent on the African dilemma.

The Senate Foreign Relations Committee, on Friday, called on the Carter administration to produce more tangible evidence of U.S. charges of Soviet-Cuban complicity in the attack on Shaba Province, which the administration said it will do.

There is strong resistance in Congress toward loosening the Vietnam war-inspired restrictions imposed on presidential options in foreign involvements.

Senate majority Leader Robert C. Byrd (D-W. Va.), who last weekend convince him that "the president's hands are tied" unjustifiably, nevertheless called yesterday for consideration of stronger action against the Soviet Union and Cuba in Africa.

Byrd, in remarks prepared for delivery to the Delta Council in Cleveland, Miss., said it is time to consider cutting back U.S. sales of advanced technology to the Soviet Union, and closing down the U.S. diplomatic mission in Havana (Cuba has a counter part diplomatic interest section in Washington).

Said Byrd ". . . the continued involvement of the Soviet Union" and its ally, Cuba, in "internal affairs and conflicts" in Africa, "indicates that the Soviet Union has not swerved from its commitment to foment chaos wherever it believes it can benefit."

Presidental national security adviser Zbigniew Brzezinski, in the Carter administration's sharpest attack on the Soviet Union, said Sunday that Moscow has violated "the code of detente" and an "international response" is required to prevent its actions in Africa from being "cost-free."

Brzezinski said on national television Sunday that the administration believes "that the evidence we have . . . sustains the conclusion that the Cuban government and in some measure the Soviet government bear the responsibility" for what he called "a belligerent act" of force against Zaire.

Guiringaud said yesterday that the French paratroops who went into Kolwezi on May 19 "haven't seen any Cubans or any [other] foreigners," but people in Kolwezi said "there were Cubans, even say Europeans and even some said there were East Germans at the begining, coming with the so-called katanga gendarmes."

"While I have no proof of it," Guiringaud said, "the only thing that can be said is that contrary to last year's invasion of Shaba, where the so-called Katanga gendermes came from [pro-Marxist], Angola, through a long trek of nearly 100 or 200 kilometers, - and they never reached Kolwezi - this time . . . the attack was made through Zambia . . .

"I do not mean by that that Zambia was involved in any way, because they had only a few kilometers to cross . . . and they have gone away through Zambia - we know it by air reconnaissance . . ."