What's behind French forays into Mideast

France's huge $1 billion sale of Mirage fighter aircraft to Egypt is only the latest indication of President Francois Mitterrand's determination to play a more decisive role in the Middle East.

It also underlines his hopes of cashing in on the overwhelming economic benefits that could result from any eventual peace settlement.

The Egyptians were originally expected to buy between 40 and 60 of the Mirage 2000 aircraft. But the high cost of the plane, roughly $50 million each including weaponry, resulted in this initial sale of 20 jets. Nonetheless, the Jan. 3 deal is the largest Egypt has signed with a West European country.

The French have also concluded a bilateral military cooperation agreement with Egypt. Under this contract, more than 100 helicopter and jet pilots as well as a dozen officers from all three Egyptian armed forces will be trained in France during the coming year. The French have further agreed to allow the manufacture of spare parts for the Mirage planes in Egypt.

France, which is Egypt's second largest supplier of arms equipment after the US regards its increased collaboration with Egypt as an open door to the rest of the Middle East. As Egypt already has considerable French military hardware on order, ranging from Mirage 5s to helicopters and Crotale missiles, a French-sponsored military-spare-parts manufacturing base would help boost sales elsewhere in the Mideast once Arab-Israeli tensions have been reduced.

Western diplomats maintain that a possible reconciliation between Egypt and the moderate Arab countries once the Sinai has been totally evacuated by the Israelis and the road open toward a resolution of the Palestinian question would encourage more Saudi and Gulf investment in Egypt.

In a two-day visit to Cairo last weekend, French Foreign Minister Claude Cheysson said that France and Egypt were ''singularly close'' concerning most problems in the Middle East, the Mediterranean, and the world in general. Mr. Cheysson also emphasized the need for a ''third path'' in helping to resolve the Middle East conflict.

''We must not allow the Middle East to be politically divided by the two superpowers as happened in Europe,'' he said. European security, he added, depends on peace in the Middle East. He also reaffirmed France's desire to participate in the Sinai multinational peacekeeping force together with the United States, Britain, the Netherlands, and Italy.

The French appear to have taken their support of the Palestinian cause a step further by calling outright for the creation of a Palestinian nation. Mr. Cheysson stressed that all people have the right to express their identity and nationality, and the right to build their own state.

''This is true for the Israeli people but also the Palestinian people,'' he said. French policy is based on the right to live within guaranteed frontiers, respect for international law, and negotiation as a means to bring about peace.

The French minister said that the Palestinian Liberation Organization should be included among the forces ''to negotiate the future.'' In the past, France only called for the right of the Palestinians to express their identity and personality.

Although France has strongly condemned the forced annexation of the Golan Heights by Israel, it remains unclear whether President Mitterrand will postpone his planned visit next month to Tel Aviv. Despite reports in the French press that this is, indeed, the case, the Elysee Palace has refused comment, and Foreign Ministry officials maintain that there is no change in policy toward Israel.

Another sign of France's hopes to improve its diplomatic and economic stature in the Mideast was Mr. Cheysson's visit last week to Ethiopia. In talks with the regime in Addis Ababa, the French arranged to improve cultural ties, including the establishment of French-language programs in schools.