Egypt signed a $1 billion agreement with France today for the purchase of 20 advanced Mirage 2000 jet fighters, a deal that may have repercussions on the additional sale of U.S. military aircraft to this country.

Announcing the agreement at the end of a three-day visit here, French Defense Minister Charles Hernu said his government will finance the sale of this "first batch" of the latest Mirage model to Egypt, but that terms for the purchase of additional planes would have to be discussed later.

The arms agreement came as Egypt's Prime Minister-designate Fuad Mohieddin completed a Cabinet shuffle that left the key positions of foreign and defense ministers unchanged, as expected, but replaced Interior Minister Nabawi Ismail, who was in charge of domestic security at the time president Anwar Sadat was assassinated Oct. 6. Details on Page A21.

Egypt had hoped to clinch a $2.4 billion deal to buy 40 to 60 of the sophisticated French warplanes, but there was no indication the two sides had reached agreement now on a larger arms package.

Nonetheless, the accord represents a major accomplishment for France, which has been seeking contracts abroad for the purchase of the Mirage 2000 to meet the costs of its production in larger numbers.

It could mean that Egypt will now use its scarce resources to buy the French aircraft rather than seeking to obtain more American-made F16 jets, the first of which are about to arrive here from the United States.

Under the present $3 billion U.S. military aid package for this country, Egypt is to obtain 40 F16 aircraft, now the most sophisticated jet in its Air Force. But local press reports prior to the latest French arms deal said the Egyptian military wanted the United States to provide another 100 to 150 F16s.

Egypt's main problem has been to find financing for its arms purchases, aimed at replacing its outdated and often immobilized Soviet equipment, particularly planes.

The Mirage 2000, powered by a single turbofan jet engine, is basically an interceptor and air superiority warplane, listed by the authoritative Jane's All the World's Aircraft as equally suitable for reconnaissance, close support and low-altitude attack missions in areas behind a battlefield.

According to the terms, as announced today by Egyptian Defense Minister Abdul Halim Abu Ghazala, France has agreed to a six-year loan in 12 installments at 9 percent interest. The loan includes a two-year grace period.

Hernu also disclosed that France has agreed to train 15 Egyptian officers, 12 helicopter pilots and 100 pilots and mechanics for the French-made Alpha jet trainer. Egypt signed an accord to buy 30 Alpha jets last June, but there are reports here that it would like to get as many as 60.

The French defense minister said he had discussed with Abu Ghazala the purchase of Alpha jets, Gazelle helicopters, Crotale ground-to-air missiles and AMX13 tanks as well as the Mirage 2000. But the only agreement announced was on the latter item.

The two governments are to set up a bilateral military committee to discuss further Egyptian arms purchases as well as joint production of some items here.

Also visiting here today was French External Affairs Minister Claude Cheysson, who said after meeting with Egyptian President Hosni Mubarak that France stood ready to "support, accompany and guarantee" negotiations for a comprehensive Middle East settlement but could not organize them. This seemed to exclude once again any fresh French initiative in the region.

Mubarak later said France, apparently through Cheysson, had promised again to participate in the multilateral peace-keeping force being organized to police the Sinai Desert after Israel completes its withdraw there April 25. Israeli opposition to the terms for European participation in the force has raised doubts whether there will now be one.