The United States and four European partners yesterday in effect sidetracked discussion of French President Valery Giscard d'Estaing's ambitious French-led Marshall Plan to bolster threatened pro Western African governments.

France's key compromise was outlined in a vaguely worded communique issued early today after more than 12 hours of closed-door discussion by American, Belgian, British, French and West German officials.

The conferees, who did no more than make recommendations to their governments, focused on Zaire's economic and security plight.

The communique said Giscard's plan - for which massive outside backing would be required - was only "touched on." It said such aid "might be provided African states desiring to preserve their integrity and development, either collectively or individually."

Examined, apparently in greater depth, were what the communique described as "the conditions under which aid should be provided Zaire to allow its economic comeback, measures either taken or envisaged to assure Zaire's security (which are) indespensible to its recovery and its economic and social progress."

Earlier in the evening French spokesman Pierre Hunt foreshadowed the limited scope of the meeting, or at least the public aspects of it. He cautioned against expecting major decisions to be announced or even taken here.

Much of the imediate urgency on the military front was diluted over the weekend when U.S. Air Force jet transport started carrying Moroccan troops to Zaire's troubled Shaba Province. The same plane will fly French Foreign Legionnaires back from Shaba to their bases on the Mediterranean island of Corsica.

There were indications that the marked for Zaire was considered more a bilateral question for the countries involved than a major subject of discussion at the conference.

Despite harsh official statements by key Carter administration figures, the U.S. delegation here, led by David Newsom, undersecretary of state for political affairs, was reported to have limited its immediate proferred military participation to ferrying other African troops to Zaire.

Symptomatic of second thoughts by nations represented here were remarks by Belgian Foreign Minister Henri Simonet, who cautioned against giving the impression the conference sought East-West confrontation in Zaire or elsewhere in Africa.

His remarks, in an interview with the Brussels newspaper La Libre Belgique, appeared aimed against both American and French activism - or at least tough recent anti-Soviet statements made in both capitals.

Giscard's troublesome Gaullist coalition allies have also expressed serious reservations about his African policies.

After some initial hopes in President Carter's more forceful foreign policy, some French commentators are beginning to wonder if Giscard was not a victim of his own wishful thinking.

Summing up the new tone of realism - after the euphoria of the Kolwezi rescue operation of European residents in the Shaba mining center - the newspaper Le Monde ran a front page headline announcing "Paris conference on Africa to define a coherent Western policy."

Conference sources indicated that Belgium wanted the economic reforms designed to reorganize Zaire's crumbling administration discussed June 13 and 14 in Brussels. That meeting, planned before the latest Shaba fighting, is being attended by the five nations present here, plus Canada, Italy, Iran, Saudi Arabia, the International Monetary Fund and the World Bank.

Diplomats predicted that Zaire President Mobutu Sese Seko would be asked to hand over many of his free-wheeling prerogatives in exchange for being bailed out once again.

Militarily, the French intervention in Shaba is coming under increasingly close scrutiny at home. Diehard Gaullists and other ultranationalists noted that France had to rely on American aircraft to ferry the Foreign Legion into Shaba. Moreover, to save weight the Legionnaires left their own parachutes at home and jumped with poorly maintained U.S. equipment provided from Zaire stockpiles.