Visiting U.S. Secretary of State Alexander M. Haig Jr. gave his support today to a French proposal for the formation of a multinational peacekeeping force to prevent Syria from overrunning the Christian sections of northern Lebanon.

French Foreign Minister Jean Francois-Poncet spoke earlier this week of an international contingent to enforce the shaky cease-fire in Beirut and around the Christian enclave of Zhle, which has been subjected to intensive Syrian artillery fire.

After discussing the issue with Haig, the French Foreign Ministry announced that the French ambassadors to Lebanon, Syria, Israel, Saudi Arabia, the United Nations and Ireland -- the current president of the U.N. Security Council -- were being summoned home for an emergency session Sunday with Rancois-Poncet.

After meetings here this morning with Francois-Poncet and French President Valery Giscard d'Estaing during a stopover between London and Bonn, Haig said: "We clearly see a role for the United Nations in this situation, and perhaps it will be necessary if the parties themselves cannot deal with it effectively to consider a peacekeeping force of some kind." c

There is apparently some hesitation about whether the force should be under U.N. auspices such as the already existing U.N. truce force in southern Lebanon because it is considered likely that the Soviet Union would veto creation of such a force by the Security Council.

Some Lebanese Christian leaders have been calling for such a force under French leadership, but Syria which is allied with Moscow, has so far resisted the idea and Syrian President Hafez Assad implicitly rejected such an approach again today.

Gaullist presidential candidate Jacques Chirac has suggested that an all-French force should be sent if necessary. A number of Gaullists have accused Giscard's government of lack of vigor in protecting the French-speaking Christians of Lebanon, who have maintained a special relationship with the Roman Catholic Church of France since the medieval Crusader kingdoms in the Holy Land.

Coming amid the tight French presidential race in which Chirac has been successfully wooing growing numbers of conservative voters from the incumbent president, the new Lebanese crisis has stirred French diplomacy into intense activity, including the dispatch of two special envoys to the region with personal messages from Giscard.

A French military transport plane returned today from Lebanon with about 25 wounded persons being brought to France for medical treatment. The pro-Socialist Party newspaper Le Matin accused the government of grandstanding and quoted the Beirut press as saying that patients had "literally to be begged" to take the plane for hospitalization in France since there is plenty of good medical care available in Beirut.

The French efforts to internationalize the latest Lebanon crisis seem to be in direct response to appeals by the Lebanese Christians, whose ties and influence in France go far beyond the traditional sentimental attachments of the church missionaries, reaching deeply into French politics, banking, business and industry.

For a French government that has often sought ways to become reinvolved in the Middle East since Britain forced it out of its mandate rule over Syria and Lebanon in 1944, such pressures and invitations to return to the region generally have been welcome.

France already provides logistical support for the U.N. force in southern Lebanon and at one time had a battalion of paratroops in the force.

Haig's statement here today that the Lebanese situation is "urgent and deserves our intense attention in the period ahead" was obviously pleasing to Francois-Poncet, who was standing next to the American as he spoke on the steps of the Elysee Palace. A French Foreign Ministry communique after Haig's departure said the secretary of state "confirms the gravity of developments that could take place in that region."