West German Chancellor Helmut Schmidt met with President Carter yesterday for talks on energy and Western defense that were notable mainly for their apparent lack of friction or controversy.

Schmidt's public stance was in marked contrast to that displayed by French Foreign Minister Jean Francois-Poncet, who concluded a visit here Tuesday. Francois-Poncet publicly expressed his government's disagreement with several aspects of U.S. foreign, defense and energy policy.

By contrast, Schmidt, who is known to have expressed doubts about Carter's leadership on several occasions, ended his two-hour, informal visit with Carter praising the talks effusively for "friendliness, frankness and productivity."

Before his arrival, Schmidt had been expected to protest the U.S. $5-per-barrel subsidy on home heating and diesel fuel imports as a disruptive factor that drives up world oil prices and harms the West European economies. Such a protest was made by Francois-Poncet.

But, when reporters asked about that issue, Schmidt waved the question aside and said he and Carter had concentrated on discussing the long-range aspects of the energy problem.

Although he has been critical of the United States in the past for allegedly wasting energy to the detriment of other industrial nations, Schmidt said he is in basic agreement with Carter "in our energy policies in particular and our economic policies in general."

Carter, who appeared briefly with Schmidt before reporters, added: "We spent more of our time on the energy question than other other single issue because it has become of crucial importance to the entire world. We recognize the importance of our acting in concert to the extent that our national interests permit."

The president's qualifying language about "national interests" hinted that differences do remain between Washington and its West European allies over energy policy. But, if there are differences, they were prepared over in a joint statement issued later by the two leaders.

It said, "They agreed on the need to reduce energy demand now and to increase energy supply over the the longer term including the use of alternatives to oil."

In addition, the two leaders discussed the Tokyo economic summit which they will attend June 28 and 29 and a variety of security issues affecting the western alliance.

Schmidt, while stressing that it was not the place of a "German visitor to mix in American political matters," warmly endorsed the strategic arms limitation treaty to be signed by the United States and the Soviet Union at the coming Vienna summit.

He said he looks forward to "swift and positive ratification" by the U.S. Senate because he regards the agreement as being in the interests of West Germany and Western Europe.

The two also discussed the Soviet buildup in Europe of conventional military forces and theater nuclear forces - those deploying intermediate-range missiles on the European main land.

At a press conference, Schmidt said they agreed that the Soviet efforts require a response by the NATO allies so that the West can deal from a position of strength in future arms-control negotations. Schmidt noted that NATO studies on modernization of western theater nuclear forces are expected to be completed toward the end of the year.

Sources present during the talks said Schmidt and Carter also agreed to try and avoid future disagreements such as the one that erupted last year over development and deployment of enhanced radition warheads-the so called neutron bomb.

Schmidt's unofficial visit came during a U.S. trip on which he is to deliver several speeches, including the commencement address at Harvard University today. Following his press conference, he left for Columbia, S.C., and a dinner commemorating the 100th birthday of the late James Byrnes, secretary of state after World War II. CAPTION: Picture, Helmut Schmidt emerges with President Carter from informal two-hour discussion of energy and defense. AP