PARIS, JAN. 30 -- France, which traditionally has relished political doctrine almost as much as fine food, has suddenly begun to suffer from an ideology gap.

Less than three months before presidential elections, a crescendo of lamentations has arisen from political commentators complaining that Frenchmen seem to believe there is little ideological difference among the three major candidates and that, no matter who is elected, the country's course will vary only slightly.

"Frenchmen are getting ready for the most prosaic, the most disabused, the most down-to-earth presidential election that could be," Andre Fontaine, editor of Le Monde, wrote in a front-page editorial. "The polls reflect their perplexity: only a minority believes victory by one or the other would change things in a lasting way, much less improve them."

While perhaps not unusual for the United States, the ideological listlessness marks a departure from the recent history of this country. French parties and their standard-bearers long have represented sharply defined ideologies, and militants have always loved arguing out a detailed program of dogma and reforms over three-hour lunches.

Only seven years ago, President Francois Mitterrand ran with a slogan promising nothing less than to "change life" in France through socialist ideology. Right-wing opponents, meanwhile, warned that his election would endanger western security and subject the country to Soviet-style regimentation.

Now, according to a poll published this week, 75 percent of those questioned believe that France would not be changed at all or only slightly changed if Mitterrand were reelected to another seven-year term. The idea of France's Socialist Party as a radical force has all but disappeared from political debate here, and analysts have begun to talk of Mitterrand as a representative of "market socialism."

"From revolutionary formulas of rupture with capitalism in 1981, Mr. Mitterrand has come around, little by little, to veritable loving kindness for private enterprise," said the rightist commentator Jean d'Ormesson.

Part of the shift, analysts here said, has come from a growing realization that grand ideological battles actually produced little change in the way people live. Recent governments, left or right, have been increasingly circumscribed by France's role as a medium power dependent on exchanges with Europe and on the world economy, they noted.

Within two years of assuming power after 1981, Mitterrand's Socialist government was forced by a falling franc and other economic realities to scale back its ideological reforms. The Communist Party, which shared power with the Socialists at first, was unceremoniously elbowed out of the government and gradually marginalized as a force in French political life.

When Prime Minister Jacques Chirac led a conservative majority back to power in 1986, the public found out that right-wing promises, such as denationalization of what the Socialists had nationalized, also brought little real change.

The basic French problems of unemployment, for example, or deficits in the national health system and foreign trade, proved as impossible to erase under Chirac's free-market ideology as they were under Mitterrand's socialism. In foreign affairs, Mitterrand and Chirac have followed with equal fervor the same prowestern policies tempered by French nationalist particularities that were set in place by Charles de Gaulle.

In the new climate, which French analysts have called the era of "soft ideology," the presidential election debate has been uncharacteristically free of grand promises or political platforms. Instead, it has been turning on candidates' personalities.

The attention to personalities rather than ideology also has intensified through increased emphasis on television, which transmits images more easily than doctrine. Television has become so important in French politics that Chirac announced his candidacy on a Saturday even though none of the major French newspapers publishes on Sunday.

For some politicians, who traditionally have thrived on ideological clashes and ringing speeches, the new climate has required adjustment.

Henri Colombier, a former member of parliament and longtime conservative activist, was trying to explain to an American reporter the other day that Mitterrand's reelection would be catastrophic because in 1981 and 1982 he did such economic harm with Socialist measures that the country is still suffering economically.

Then, looking down at the table where he had just eaten an appetizer of foie gras and was about to dig into a generous serving of Charolais beef, he smiled and said, "Maybe you should have been served sandwiches if I was going to tell you that."

Mitterrand, by refusing to say whether he will run again and holding to a stately presidential pose, has succeeded in focusing much of the personality debate on himself, contributing to the ideology-free campaign. Although his Socialist Party has drawn up a program as usual, political discussion has ignored it, concentrating instead on the president's popularity in the polls and the guessing game about his intentions.

A top story in the press this week, for example, was a comment in a magazine by Mitterrand's wife, Danielle, that she soon would no longer be the wife of a president. At the same time, Michel Rocard, a would-be Socialist presidential candidate, was given a boost because he had breakfast with Mitterrand and was authorized to say the president would tell France sometime in March whether he will run or not.

On the right, Chirac and his main conservative rival, former prime minister Raymond Barre, have advocated continuing France's free-market economy with extensive state controls. So far, they have differed mostly over competing claims for efficient management.

"They are both Gaullists, and they are both liberals," d'Ormesson wrote recently. "What opposes them, when you get down to it, is that there is only one chair for the president of the republic in the Elysee Palace, and there are two of them who want to occupy it."