France has launched a concerted campaign to reestablish a significant French presence in Southeast Asia, both politically and economically.

Although the most visible sign of the decision is a major export drive covering technology in nuclear energy, transport, aeronautics and weaponry, diplomats in the region say that the new offensive is only secondarily economic.

Earlier this year, French ambassadors assigned to the Pacific region were summoned home to be briefed on President Francois Mitterand's concept of a modest but "global role," different from that of the French colonialists in Indochina but, nonetheless, a visible alternative to the United States and Soviet Union. The spearhead of this policy is to be in Southeast Asia.

A senior French diplomat in the area said, "This explains our renewed interest in Vietnam. If we were only interested in markets, we would not be there, as the Vietnamese have no market to speak of."

Part of the responsibility for the French initiative is Foreign Minister Claude Cheysson's. During 1952-54, Cheysson was deputy diplomatic adviser to the French high commissioner in Saigon and in 1966-70 was ambassador to Indonesia.

During the intervening years, he was a pivotal consultant to the French government on Asian affairs. Cheysson is reported to have said "it is not normal that France be absent from Southeast Asia." He and Mitterand are looking to redress what they see as an imbalance created by France's neglect of the region since the "loss" of Indochina.

However, recent French official forays to Asia are also due to a shift in Mitterrand's domestic policy. The Socialist government's attempts to revitalize the economy -- raising the minimum wage, encouraging consumerism and fighting unemployment -- have only partially succeeded.

Rising consumerism resulted in a greater trade deficit as the French turned to foreign imports. Investment and confidence has not returned to a worried commercial sector. Capturing billion-franc sales of Framatone nuclear reactors, Citalcatel telecommunications systems, Aerospatiale Ecureuil helicopters and airbuses in Asia might win over the skeptical industrialists to a Socialist government they did not support.

Raising the profile of what Cheysson calls "Socialist foreign policy" while soliciting business has necessitated a dual approach to Southeast Asia. Last spring, Science and Technology Minister Jean-Pierre Chevenement went to Hanoi to promise more monetary and food aid in exchange for increased cooperation on the humanitarian front.

A few weeks later, Vietnamese Foreign Minister Nguyen Co Thach was in Paris for successful talks with Cheysson on the rescheduling of Vietnam's $300 million private and official debt to France.

To assuage alarm among noncommunist Asian governments at the expanding French -- Vietnamese relationship, Mitterrand then sent conservative Gaullist Michel Jobert, currently external trade minister, to Thailand, Malaysia and Singapore in May. Jobert had lent Mitterrand's anti-Giscard campaign more impartial credibility with a staunchly anticommunist government like Prime Minister Lee Kuan Yew's here.

Jobert traveled with 41 members of the French private sector setting up a joint committee in Malaysia and Singapore for trade and cooperation in industrial ventures.

In Malaysia, Jobert parried complaints from local trade and industry officials that France's new policies to revive the domestic market would hurt Malaysian exports to the European Community.

Although the Mitterrand government's stated policy is to phase out defense sales after honoring existing contracts, Jobert lent a high profile to Aerospatiale's current bid to sell Singapore's Ministry of Defense 30 to 40 helicopters.

Touring Singapore in one of the light-weight five-seaters, he stated with a flourish to the press, "We are the world's leading exporter of helicopters. Many don't know this. That's why I flew in one here today." Before leaving for trade talks in Burma, Jobert signed a five-year trade pact with Singapore, promising aeronautical, electronic, data-processing and oil-industry equipment, as well as energy, technology and sea exploration.

To the south, the French were wrapping up details of their recent $800 million contract to extend Indonesia's Krakatau steel complex in West Java. The Creusot Loire team, together with two Spanish engineering companies, beat out Japanese firms. Further fostering of economic links with Indonesia will come with Mitterrand's proposed visit to Jakarta before the end of this year.

In the long term, France is hoping not just to invest in the growth economies of Asia, but to lure some Asiadollars into joint investments in third countries or in France.

Singapore alone has surplus funds of $7.1 billion from foreign-exchange and budgetary surpluses and is choosing investments in the United States, Australia, Japan and Europe. The French are active suitors.

"We have recovered from the trauma of losing Indochina, and we have no intention of letting our regrettable absence from Asia continue," said the French diplomat.