After five years of relative harmony on global matters, new strain are surfacing in French-American relations as the energy crisis and the Egyptian-Israeli treaty drive Washington and Paris onto different courses.

During the two-day official visit by France's new foreign minister, Jean Francois-Poncet, these strains emerged clearly, as did the efforts to contain them within the working relationship the two nations have established since President Valery Giscard d'Estaing came to office in 1974.

Throughout the visit, Francois-Poncet expressed to President Carter, other senior officials and the press France's preoccupation with the need for immediate steps to ease the oil supply squeeze and for long-term "concerted action" by oil-importing nations to cut imports.

Specifically, he proposed that the United States and its major trading partners agree at the coming Tokyo economic summit to apply tight controls on spot market prices in Europe for crude petroleum, as the first step in a campaign to stop speculation and stabilize prices. France also formally asked the United States yesterday to stop providing a $5-a-barrel entitlement payment to U.S. companies for imported heating oil.

The Carter administration's emphasis was on the Middle East peace treaty in Washingttn March 26 and France's "disappointing" failure to support it. Carter told the foreign minister during a 20-minute meeting that this "tends to strengthen the radicals and force moderates (in the Arab world) to vacate the middle ground."

Despite the strians, however, both U.S. and French officials noted tte sharp contrast between the softly worded, more-in-sorrow-than-anger exchanges of the past two days and the frequently agressive anti-Americanism that marked Gaullist policy until the death of President Georges Pompidou in 1974.

Francois-Poncet conducted a wide-ranging press conference with the candor and vigor of a man determined to break with the somewhat stuffy image that French diplomacy has long projected abroad. He left no doubt about France's view that urgent action is needed to convince oil producers and America's European allies of U.S. resolve to adopt an effective national energy policy.

He asserted that oil-importing nations must eliminate speculation and competition that has driven prices in the spot market at Rotterdam to twice the official price of the Organization of Petroleum Exporting Countries, or else "the West will be committing energy suicide."

Conversations on Monday with Carter and other officials, including Energy Secretary James R. Schlesinger, convinced him that a major reform of the spot market "is a shared goal," Francois-Poncet said. But administration officials said privately they were not sure how this could be accomplished and noted that West Germany is strongly opposed to the French proposal.

Francois-Poncet predicted that energy would be "at the center" of the Tokyo summit this month, where "binding decisions have to be taken" to reduce imports and avert a more intense scramble among developed countries for oil at any price. One mechanism he mentioned was agreement on a possible fixed ceiling for the price of imported oil.

Appointed foreign minister in November, Francois-Ponet is one of Giscard's closet associates and many French analysts feel he is being groomed to become prime minister in the near future. He also came to Washington as the current head of the Common Market's Ccuncil of Ministers.

At his press conference, Francois-Poncet:

Again voiced France's strong fears that the Egyptian-Israeli peace treaty could turn out to be only a separate agreement" that would "divide the Arab world" and not bring "a solution to the West Bank question, which in fact is the Palestinian problem." The Carter administration denounced on Monday Israel's decision to start a new civilian settlement on the West Bank, he noted, "but the settlements are going on. Even the moderate Arab countries feel that nothing more will follow."

Said France supported "in principle" the strategic arms limitation treaty (SALT) reached by the Soviet Union and the United States, but added that it would reserve judgment on the effectiveness until the full final text is released.

Asserted more clearly and forcefully than before that France will not participate in the next round of strategic arms talks, known as SALT III.France is "going to great technical and financial effort" to modernize its own modest, medium-range nuclear force and probably would not consider being involved in the SALT process unless Soviet and U.S. nuclear arsenals had been reduced to a size equivalent to that possessed by France, he said.