Mitterrand heads for Syria to pressure Assad on PLO, Lebanon

Fresh from his controversial meeting with Libyan leader Muammar Qaddafi, French President Francois Mitterrand plans to meet with Syrian President Hafez Assad this week.

Whereas the United States government disapproves of Mr. Mitterrand's Libya connection, Washington looks favorably upon his plan to visit Syria, according to reliable French and American sources.

''Mitterrand's trip to Syria is aimed at striking a balance as far as French Middle Eastern policies are concerned. Mitterrand has already journeyed to Amman (Jordan), Tel Aviv, and Riyadh (Saudi Arabia). Syria is considered in Paris to be a major player in the area and basically as a potential stabilizing force,'' says a well-placed Western diplomat.

In particular, Mitterrand will try to dissuade Mr. Assad from formally splitting the Palestine Liberation Organization, says a highly placed French official.

PLO chairman Yasser Arafat plans to convene the Palestine National Council in Amman tomorrow. Assad is expected to convene a rival national council in Damascus, which would officially split the PLO.

Mitterrand will also try to persuade Assad to allow the Lebanese to be flexible in their talks on an Israeli pullout from south Lebanon, the French official says. Syria, though not formally participating in the talks, is the main power broker in Lebanon.

According to this official, Mitterrand's other objectives include:

* Improving relations with Syria. Once excellent, they had deteriorated in recent years to the point where a French ambassador, Louis Delamare, was assassinated in Beirut, by agents believed to be working for the Syrian secret police.

* Restoring French influence in Lebanon.

* Improving, through Syria's good offices, French-Iranian relations. France has provided economic and military support to Iraq in its war with Iran, which Syria backs. France is looking beyond Iranian leader Ayatollah Ruhollah Khomeini and wishes to reduce Iranian hostility toward France.

* Adding credibility to France's political and economic role in the Mideast, Saudi Arabia in particular. The Saudis, who do not want Syria to be the odd man out in the Mideast, would be pleased if French-Syrian ties became warmer.

* Partly filling the diplomatic void left in the area by the American withdrawal from Lebanon.

''Mitterrand will be walking on a tightrope,'' says a UN official knowledgeable on Mideast affairs. ''Egypt and Iraq are not opposed to France's mending fences with Syria - to a point. If Mitterrand becomes too cozy with Assad, then (Egyptian President) Hosni Mubarak, (Iraqi President) Saddam Hussein , and Ronald Reagan might be angered.''