It was billed as the biggest and most eclectic gathering of intellectuals and cultural figures ever held. Sophia Loren sat cross-legged on a settee talking to Melina Mercouri. Graham Greene struck up a conversation with John Kenneth Galbraith. Peter Ustinov shook hands warmly with Franc,ois Mitterrand.

For the past two days, nearly 300 representatives of the world's artistic and intellectual elite have been engaged in a collective brainstorming officially titled "Creation and Development." Under French government auspices they have discussed the weighty subject of how to solve the economic crisis, and occasionally delved into such topics as the insidious cultural threat posed by the American television series "Dallas."

At the end of the congress, marked by a glittering reception at the Elyse'e Palace hosted by President Mitterrand, the participants seemed to have difficulty pinpointing exactly what had been achieved. But they all agreed that the occasion had been unique.

As Francis Ford Coppola, himself no stranger to mammoth undertakings with films such as "Apocalypse Now" to his credit, remarked: "Well, nobody else has thought of this kind of meeting before. The French have done it--and nobody else has."

Surveying a roomful of writers, actors and philosophers drinking champagne and munching smoked ham sandwiches, economist Galbraith sniffed: "Only a journalist would ask if this was actually useful."

Asked what original ideas had come out of the meeting, the author of "The Affluent Society" thought a bit and then replied: "Well, I found Norman Mailer's proposal for a tax on plastics very interesting."

Mercouri, described on the official list of participants as "comedian" rather than as the Greek minister of culture, took a serious view of the congress. "This is the first time anything like this has happened. It's a marriage between intellectuals and the economic crisis. United, we can be the biggest force for peace in the world," she said.

There were occasional grumbles too. Ustinov complained that he found the seats in the great hall of the Sorbonne "uncomfortable." Mailer said his French wasn't good enough to follow much of the rhetoric delivered beneath the busts of such great men of French letters as Descartes and Pascal. Mary McCarthy used words like "vague" and "boring" to describe many of the speeches in her special commission, which was devoted to "culture and change." Feminist writer Kate Millett complained about the paucity of women at the meeting, saying that "you are shutting your eyes to half of mankind."

Perhaps the most important aspect of the congress was the social mixing of intellectuals from different disciplines. "We met old friends and made new ones," remarked McCarthy.

"I don't think for a moment that the rate of inflation will drop by a single point as a result of this meeting. What happens here is by nature indefinable," Ustinov said.

Around and about stood long-haired artists in shabby clothes, eminent scholars, filmmakers and Nobel prize laureates. The guest list read like an extract from "Who's Who of World Culture." Gabriel Garcia Marquez, the Colombian winner of the Nobel prize for literature, was there. So too were film directors such as Sidney Lumet, poets such as Leopold Senghor, and a gaggle of American writers such as William Styron, Susan Sontag and Robert Penn Warren.

Ustinov praised France's Socialist government for bringing them all together. "This is an extraordinary initiative from a government. Governments of the left are always much better at this sort of thing because they give the appearance of at least wanting to learn, while governments of the right want only to teach."

The holding of the congress reflected the present French government's hopes of promoting French culture and communications technology, particularly in the Third World. The link between culture and economics was stressed by Mitterrand in his closing speech in which he invited the participants to "prepare for the moral rejuvenation of the world."

Mitterrand said the solution to today's economic crisis lay neither in traditional liberal capitalism nor state socialism of the kind embodied in Eastern Europe. France, he said, was investing heavily in technology--but the new information systems had to be fed by cultured and intelligent human beings.

The French organizers refused to say how much the congress cost. Many participants were in France already, but others were flown across the Atlantic on Concorde at government expense and installed for the weekend at luxury hotels in Paris.

The congress appears to have been intended partly to clear up ill-feeling that resulted from comments by Jack Lang, the French minister of culture, who called last July for a crusade against American "culture imperialism." The subject cropped up in several speeches, including one by an Israeli writer, Amos Kenan, in which he said that his hometown of Tel Aviv had come to resemble Texas since everybody stayed at home to watch "Dallas."

The American television series, which has taken Europe by storm, was defended by Norman Birnbaum, professor of sociology at Georgetown University. " 'Dallas' seems to be the vogue word around here . . . but is it really so bad? It gives pleasure to a large part of mankind," he said.

Despite the theme of the congress, there were few specific suggestions as to how culture could help solve economic problems. Perhaps the most original came from a writer who said that governments should encourage millions of unemployed people to become artists.