Although it is run by a president who declares himself a "friend of Israel," France's new Socialist government has slipped effortlessly into the traditional ways of French Middle East policy Israelis previously denounced as a sellout to Arab oil.

The line taken by Paris is observed with particular attention these days in the Middle East and in the United States. As the Reagan administration ponders how to move the Camp David process forward, Europe seems determined to make its own contribution, and France's diplomacy will be decisive.

French positions flow in part from a conviction -- espoused by officials from President Francois Mitterrand on down -- that the Arab-Israeli conflict creates a permanent danger of war and that it can be solved only by dealing with the Palestinian desire for a homeland, officials say. The unsaid part is that these positions also reflect France's broad and vital economic links with the Arab world, including oil imports, military and manufacturing exports and Arab investments.

France gets three-fourths of its oil from Arab countries. Eleven percent of its exports go to the Arab world, including $2.8 billion annually in arms sales. One multiyear naval construction contract alone is scheduled to bring in $3 billion from Saudi Arabia. In addition, the Arabs' share of $130 billion in foreign investment in France is estimated to be $30 billion.

These convictions and interests have not changed with Valery Giscard d'Estaing's departure from the presidency. As a result, French diplomats say, the only real shift in Middle East policy is a flavor added by Mitterrand that is the fruit of his personal sympathy for Israel and long association with Israeli Labor Party leaders such as Shimon Peres in the Socialist International.

"Our policy is about 90 percent the same," said a Foreign Ministry official. "And the 10 percent difference is really a difference of accent."

On one hand, dealing as president with Prime Minister Menachem Begin's Likud government in Jerusalem is not the same as debating with Labor delegates at Socialist gatherings.

On the other, analysts in Paris believe some Israelis may have read too much into Mitterrand's declarations of friendship. For along with his sympathy for Israel, he consistently has advocated a Palestinian homeland as a way to rid the Middle East of its perennial Arab-Israeli tension -- a principle anathema to Begin and opposed by most of the Labor Party as well.

As the "new policy" unfolded over the past three months, therefore, it turned out to be not so new. As a result, the Israeli government has expressed its disappointment and "worry" in public statements from Jerusalem and in private contacts between Israeli Ambassador Meir Rosenne, Mitterrand and Foreign Minister Claude Cheysson.

It was Cheysson's trip last week to Jordan, Syria and Lebanon that drew the strongest Israeli complaints.

The foreign minister, who dealt widely with Arab countries in his previous post at the Common Market, emphasized in declarations calculated to please his hosts the French position that Palestinians must have a homeland with "state structures." In addition he dramatized French policy holding that the Palestine Liberation Organization is "representative" -- although not the only representative -- of the Palestinian people, in a much-publicized meeting with PLO leader Yasser Arafat in Beirut.

There was nothing really new in such a meeting. France's then-foreign minister, Jean Sauvagnargues, met Arafat in October 1974. The PLO has had authorization to maintain a quasi-diplomatic representative here since 1975.

But many Israelis and other observers were struck by it because they had expected Mitterrand's well-known friendship with Israel to change the course of French policy.

Perhaps more important, there was no rolling back from Cheysson's statement that the Camp David accords failed to offer a possibility of solving the Middle East conflict because they neglect the Palestinian problem. This flew in the face of the U.S. and Israeli contention that the Camp David talks on West Bank and Gaza autonomy, excluding the PLO, represent the appropriate way to deal with the Palestinians.

Rosenne saw Mitterrand and Cheysson this week to make what reports from Jerusalem said were pro forma protests of the Cheysson trip.

Israeli diplomats here and French Jews appeared especially upset at Cheysson's comparison of Palestinian resistance against Israel with French resistance against Germany in World War II. Although French officials explained the statement as a simple assertion that aspirations such as the Palestinians' were bound to lead to armed resistance, the mention of Nazi Germany seemed calculated to grate Israeli and Jewish nerves.

Cheysson is not alone in paying close attention to the Arab world. Mitterrand himself this month is to make his first major foreign trip, besides the Ottawa summit, to Saudi Arabia. He already has received the Saudi monarch, King Khalid, in Paris.