The scene was the first Elysee Palace press briefing after the news that President Valery Giscard d'Estaing had accepted diamonds from the self-proclaimed Central African Emperor Bokassa. But Giscard's spokesman, Pierre Hunt, droned on with details of the president's provincial tours and other trivia. Only when it was evident that no French reporter would ask about the diamonds did one of the four foreign newsmen present raise the question. And all of the follow-up questions came also from the foreigners.

The French have a natural sense of respect and discretion about embarrassing questions. It is part of the civility that the world associates with France. It is also one of the reasons why this nation, with its great tradition of press freedom, has almost no tradition of investigative journalism.

In fact, all of the major stories that have shaken the French establishment in recent years -- Giscard's diamonds, Prime Minister Raymond Barre's real estate deals, former Prime Minister Jacques Chaban-Delmas' tax avoidance -- have been the work of a single publication, the weekly Canard Enchaine. The rest of the French press has waited for the Canard to turn up something juicy, and then has commented on it.

There is a strongly expressed view here that French society is too fragile to stand much of the kind of Watergate-like investigative reporting the Canard has been doing. As sociologist Jules Monnerot put it, "I shudder to think that freedom of the press understood in this way would have ended the careers . . . of Cardinal Richelieu for being decidedly too friendly with his niece and of Louis XIV, who made so much work for his confessor . . . "

The French are ardently attached to the free debate of ideas, but freedom of information is another matter. And the French government has been strengthening its hold over the information outlets.

Giscard has been consistently replacing Gaullists with personal political allies at the command levers of the state's television and radio networks and even of the popular commercial radio stations, in which a state holding company owns controlling interests.

Radio Luxembourg, the most independent station because of its connection with the Luxembourg government, rejected dozens of Giscard's candidates for its presidency before finally accepting Jacques Rigaud, executive assistant to Giscard's foreign minister.

The news agency Agence France Presse last fall lost its rearguard fight to keep respected press figures at its head.

Henri Pigeat, a former government information official, took over the very day that the Canard published the first story about Giscard's diamonds. AFP waited until the next day to put out the story, and then only after a scathing statement by the journalists' union that the agency's credibility was at stake.

The former head of a state radio station recalled that Giscard's press spokesman, Hunt, would call the station to complain about such things as the use of a news story about a bomb explosion at a Paris luxury food shop as the first item in a newscast. "Giscard's liberalism in the information field," the former radio executive said, "consists in letting you do what you want and reproaching you afterward instead of issuing orders beforehand. The result is self-censorship."

A parliamentary inquiry into freedom of information in France ended in September after hearing 93 witnesses, mostly journalists, behind closed doors. sThe investigating committee, chaired by a Gaullist deputy, dissolved itself after being unable to agree on any conclusion. All of the testimony will remain secret, because it was agreed that none of it could be published if any one witness objected, and all the witnesses and committee members were warned that they would be subject to heavy penalties if they made any of the proceedings public.

Several weeks later, the suicide of Labor Minister Robert Boulin brought attacks on the press by virtually the entire French establishment, led by Giscard Barre and Chaban-Delmas. One prominent deputy called for stronger libel laws to put any convicted publication out of business and its publisher behind bars. Most of this anger was aimed at the Canard, a modest eight-page paper that accepts no advertising and sells most of its half-million copies on provincial newsstands.

Better-financed publications don't match the Canard's digging. Claude Angeli, who directs the weekly's investigative staff of 11 full-time political reporters, says "the problem in France is to find real information hunters. There aren't that many around."

As Jean-Claude Guillebaud, a top reporter for the leading establishment paper, Le Monde, put it recently, most serious French journalists regard information-gathering as "work for apprentices" and prefer to write editorials and commentaries on other people's reports. If other papers did their job properly, Guillebaud said, the Canard could not play its role.

Until recently, Le Monde, the organ of the Paris intellectuals, was as passive as the rest of the French press. But its editor, Jacques Fauvet, played the Canard's allegations about the Bokassa diamonds very big. His front-page editorial, a two-page spread about the business dealings of Giscard's family and a story recalling previous French presidential scandals turned the Canard's revelations into a serious affair.

Giscard's reaction, Fauvet confirmed in an interview, was to call him at home to "scold" him about the articles on his family. Fauvet's response was to assign several reporters to an investigation of Giscard's "personal Africa policy."

But "we're not the Canard," Fauvet said. "No one feeds us documents. Besides, the French press is not the American press . . . In this country, people would rather circulate rumors than issue information. When we seek information, we get the door closed in our face.

"There is also a difference in mentality. French public opinion is so blase.People just assume politicians are dishonest. So how can you expect those people to support the press if it reveals scandals?"