The tragicomic tale of how a team of bogus inventors bilked a former French government out of about $200 million has touched off a complex round of political maneuvering between the ruling Socialist Party and its right-wing opponents.

A fresh impetus to the scandal, which has become known as the "sniffing planes" affair, was provided this week by the publication of a secret report describing an almost farcical series of experiments into new methods of oil detection.

The 150-page report shows how the "inventors" managed to convince former president Valery Giscard d'Estaing and the state-run oil company Elf-Aquitaine that they were on to something "that could change the fate of France, even the world."

The hoax was discovered in May 1979 when a prominent French scientist denounced the futuristic machines that could allegedly "see beneath the ground" from high altitudes as an elaborate hoax. But the affair was hushed up by the government at the time because of the potential political embarrassment and damage to Elf's international reputation.

During the past few days, the "sniffer planes" scandal has developed a soap opera quality that has drawn the attention of the nation.

The cast of characters includes an eccentric Belgian count, Alain de Villegas, who "invented" the sniffer device; his mysterious Italian associate; the president of a Swiss bank; a couple of former French secret service agents; secretive captains of industry, plus the politicians themselves, who were suddenly revealed in a gullible new light.

In addition to providing ammunition for the classic left-right confrontation that lies at the heart of French politics, the scandal has illustrated the more subtle personal rivalries within the ranks of the opposition. It has become part of a continuing political game that could have an important impact on France's presidential elections in 1988 and beyond.

The current prime minister, Pierre Mauroy, presented his decision to publish the official report on the affair as a reflection of the Socialist Party's high-minded commitment to a more open style of government. A more plausible explanation, in the view of most political analysts here, was his careful calculation of the likely electoral advantages to the Socialists of holding their predecessors up to public ridicule.

Aside from Giscard, the politician who stands to lose most from the scandal is Raymond Barre, a former prime minister who ordered the independent Court of Accounts to keep its investigation into the affair quiet, leading to the Socialists' indignant charges of a cover-up.

At Barre's instigation, the chairman of the court destroyed three of the original six copies of the report. The remaining copies were kept by Giscard and Barre after they left office and came to light following an investigation by the satirical weekly Le Canard Enchaine.

The authoritative Paris newspaper Le Monde reported this week that Barre viewed the present government's handling of the scandal as a political ploy designed to harm him and build up his main potential right-wing rival, Jacques Chirac, who heads the neo-Gaullist RPR party. Chirac, who also was a prime minister under Giscard, has sought to depict himself as a disinterested observer.

Barre, with his reputation for competence and honesty, is viewed by the Socialists' electoral strategists as the most serious potential challenger to President Francois Mitterrand. He has managed to cultivate a more centrist, liberal image than Chirac.

Few analysts give Giscard a serious chance of regaining the presidency following his defeat by Mitterrand in May 1981. The "sniffer plane" affair comes on top of a series of other scandals that called into question his personal judgment.

In a press conference Monday, Mauroy specifically absolved Chirac--who was prime minister under Giscard in May 1976 when the initial decision to go ahead with the "sniffer planes" project was made--of responsibility for the fiasco. He accused Giscard of keeping the affair secret from his prime minister until October 1976, by which time Chirac had been replaced by Barre.

Barre, meanwhile, has sought to present himself as the passive executor of Giscard's wishes. His aides argue that it would have been very difficult for a prime minister to question a project that had been personally approved by the president and backed by the French scientific establishment.

Until the very end, independent experts never got a chance to test the count's sniffer machine for themselves because of the secrecy maintained around the project.

The trial demonstrations were conducted exclusively by Count de Villegas' Italian associate, Aldo Bonassoli, who is presented by the report as the only authenticated villain of the affair.

Conclusive proof of Bonassoli's trickery came only in May 1979 after the government appointed a leading nuclear scientist, Jules Horowitz, to investigate.

The report quoted Horowitz and successive Elf chairmen as certain afterward that "everything was false and faked from the start." The report, however, leaves open the possibility that some of the early results may have been genuine, with Bonassoli resorting to fraud when the machine proved incapable of sophisticated experimentation.

Tracked down in northern Italy by French journalists, Bonassoli continued to express faith in the "sniffer" machines and denied that he had made any money out of the affair. But he declined to discuss the experiment in detail, saying that it was still "secret." Count de Villegas, meanwhile, has disappeared.

A revealing aspect of the affair is the controversy that publication of the report has aroused.

The independent leftist newspaper Liberation remarked in an editorial that the practice of releasing such official documents may be routine in the United States but is "absolutely exceptional" for France's secretive and centralized bureaucracy, which "instinctively fears public accountability like the bubonic plague."