Less than a year after losing a second-term presidential bid to Socialist Francois Mitterrand, Valery Giscard d'Estaing is running hard for what used to be one of the lowliest elective offices in French politics.

The fact that Giscard, 56, is officially on the comeback trail is considered more important than the race itself for county elections later this month.

Giscard is campaigning eight hours a day for fewer than 12,000 potential votes and is sticking to local themes. On one recent outing he talked to residents of a retirement home, supermarket shoppers and athletes at a sports center.

Even his veteran Socialist opponent concedes that Giscard is a sure winner on his home turf of Chamalieres, the well-to-do suburb of industrial Clermont-Ferrand in south-central France.

Giscard's decision to make a comeback has not been without its detractors who dismiss his starting out at the bottom as false modesty. His stiff, patrician manners, which enraged many French citizens last year and heavily contributed to the Socialist victory, is still in evidence.

Once beyond the confines of Chamalieres, where he is considered something of the lord of the local manor and, in fact, owns a castle, Giscard has run into what the late president Charles de Gaulle called his "problem: the people."

Some remarks he made on national and world problems in interviews published in Germany's Stern magazine, France's Paris-Match and the Sunday Times of London were not well-received.

There is also the problem of the apparent lack of warmth in Giscard's relations with the quarreling remnants of his Union for French Democracy party, especially with his former prime minister, Raymond Barre. Barre has done his best to give Giscard a wide berth for his comeback attempt.

Officially, Giscard has done his best to play down his lingering distaste for neo-Gaullist Paris Mayor Jacques Chirac, whom he accused of "premeditated treason" for allegedly encouraging the Gaullist faithful to withhold their key support last May, contributing to his election debacle.

Political analysts believe that one of Giscard's main motivations in running now in Chamalieres is to prevent Chirac and his Rally for the Republic party from nailing down the undisputed leadership of the conservative opposition.

But Chirac still looks like the opposition leader and has used his efficient stewardship as mayor of the capital to confer with Mitterrand on the capital's problems, but take him to task on national political questions.

Nonetheless, Chirac and Giscard have agreed to field only one conservative candidate in most of the nearly 2,000 cantonal voting districts being disputed on March 14 and 21. Every three years half the cantonal councils are up for reelection.

In part, such conservative prudence is dictated by fears that the Socialists are still riding a wave of public support even if Mitterrand's political honeymoon is wearing a bit thin.

In part it also reflects the Socialists' decentralization reform, which will transfer some power from Paris to the general councillors elected in the cantonal vote.

That explains why the Socialists are not adopting the traditional view of the party in power to dismiss cantonal elections as essentially apolitical, particularly when such elections were lost.

The Socialists and the Communists--nominal comrades in the Socialist-dominated government, but fierce rivals in the local elections--are also campaigning hard.

Socialist Secretary General Lionel Jospin has predicted that his party will win about 30 percent of the vote and capture more than half of the general councils.

Conservatives, meanwhile, have charged that the Socialists' redistricting, which the government had defended as long overdue, amounts to gerrymandering.

The government does seem to be taking the elections seriously, judging by the way it seems to be buttering up the electorate.

A 3-cent cut in the price of a gallon of gasoline was the first drop in 17 years. During the past few weeks there also have been promises to middle-class executives that they will not be taxed more heavily, the poorest of the French have been told that the government-operated savings accounts now will be indexed to protect their savings, and women have been promised partial reimbursement for abortions.

The opposition has been reduced to flogging a perennial grievance--the quality and objectivity of state-run television. At times it seems the conservatives are repeating the arguments the Socialists and Communists voiced during their 23 years in the political wilderness.