The French Communist Party, which is the closest to the Kremlin of the major Western communist parties, said today that West German Chancellor Helmut Schmidt's trip to Moscow proves that the world balance of power has tipped in favor of the Soviet Bloc.

The French Communist newpaper L'Humanite indicated in a front-page editorial that the Soviets intend to press their perceived advantage in Western Europe by demanding that France-in particular should renounce any plans to deploy neutron weapons.

French President Valery Giscard d'Estaing said last week that France has tested the high-radiation nuclear artillery shell that kills but does minimal damage to property and equipment. It is generally viewed as a potential equalizer against the immense Soviet superiority in numbers of tanks. Giscard said he will not decide whether to issue the weapon to French forces until well after next year's elections.

L'Humanite said Soviet President Leonid Brezhnev's call during the Schmidt visit for an international ban on new weapons of mass destruction, including the so-called neutron bomb, was a direct response to Giscard's announcement.

The French Communist Party's warning to Giscard that he had better bend to Soviet demands came as U.S. Defense Secretary Harold Brown said on French television that Western Europe cannot maintain its independence from the Soviet Union without American help.

"I do not believe," said Brown in an interview taped yesterday but broadcast today, "that, given the enormous Soviet military force, that Europe can, by itself, sustain political independence. . . . Western Europe and the United States together can offset Soviet military force." He said the "mistaken belief," encountered during three recent trips to Europe, that the United States is slipping "could lead to neutralization which would readily be just another term for a surrender to Soviet domination because Europe really has not much choice in this matter."

The interview was taped before a meeting of almost two hours between Brown and Giscard. The French president is known to share with Schmidt the strong feeling that U.S. world power is on the wane.

Saying essentially the same thing as Brown did on French TV in a different way, L'Humanite said: "The world balance of forces in favor of the U.S.S.R. and the other socialist countries is so strong that . . . the leading European capitalist powers are in no position to place Moscow in quarantine."

The Communist paper said that Western Europe's economic interests, "particularly large in the case of" Western Germany, also work against any efforts to isolate the Soviets.

This apparent reference to the economic package that Schmidt and Brezhnev signed in Moscow yesterday apparently reflects the Soviet view that their trade ties with Western Europe can offer political leverage. A Sovet source in Paris noted that the economic package means a number of jobs for West Germany and is bound to boost Schmidt in his reelection struggle against the opposition Christian Democrats.