That glory of the continental breakfast, the croissant, the light and flaky crescent-shaped French roll, has become the symbol of a major political confrontation over government attempts to freeze food prices.

Prime Minister Raymond Barre's decree placing price ceilings on a long list of baked goods and other foods so angered one baker that he provided square "croissants" - same dough, same taste, but ill-suited for dunking in the morning coffee.

Barre further angered France's powerful shopkeepers by cutting the prices of draft beer, certain wines and some meats and by lifting a 1973 regulation that barred construction of large stores in neighborhoods where local shopkeepers did not want them. Thanks in part to that law, there are only 657 supermarkets in all of France.

The conflict between Barre and the country's 250,000 small shopkeepers, a well-organized and powerful force in French politics, has distracted the country from the continuing name-calling within the once-allied leftist opposition.

Barre's decision to take on the shopkeepers is a calculated risk just four months before crucial National Assembly elections. Starting with the shopkeepers' revolt in 1956 led by Pierre Poujade, whose party threw a fright into traditional politicans by winning 12 per cent of the vote and 52 Assembly seats. French small businessmen have been a force to contend with.

They are articulate and can complain directly to their fellow Frenchmen. In one neighborhood cafe last week, a waiter was telling his customers to take it up with Barre if they did not like the size of the portions.

"We'll respect the prices, but we'll reduce the amount you get," said the waiter to a customer who was served a one-egg omelette for $1.

The cafe's usual list of sandwiches had been halved and those that remained on the menu were all set at the ceiling price of 80 cents. Gone from the menu were such items as roast beef and grilled cheese sandwiches, judged too unprofitable at 80 cents. Also on the restaurateurs' boycott list were mixed sandwiches like cheese and tomato, although you could order a cheese sandwich and a tomato salad and make your own.

That kind of guerrilla warfare was easier to digest than a two-day strike of bakeries and the shutdown for a day of practically all the restaurants in the Paris region - from the local pizzeria to the great gastronomic palaces decorated with stars of the Michelin guide. In Montparnasse, once the neighborhood of F. Scott Fitzgerald and Ernest Hemingway, all their old hangouts were dark and there were lines until past 1 a.m. at the only eating place open for blocks, a Breton creperie.

Gerard Nicoud. the successor of Perre Poujade, immediately called on his followers to "revolt," saying, "Barre is following the policy that (communist leader Georges) Marchais would like to apply He is offering to the collectivist supermarkets the monopoly of distribution in France on the backs of the hundreds of thousands of shopkeepers.It is the end of all liberal policies."

Paris Mayor Jacques Chirac, the heasd of the Gaullist party and the rival of President Valery Giscard d'Estaing and Prime Minister Barre for control of the government majority, rushed to the defense of the shopkeepers. In recent months, the Paris police have already forced the closing of three discount food stores by the simple device of blocking the parking lots and issuing tickets to anyone trying to park nearby.

Such attitudes have contributed in large part to the undoing of Barre's September 1976 anti-inflation program, contributing in turn to a growing public bitterness that many analysts think goes far to explain the electoral lead of the leftist opposition in the opinion polls. In October, food prices rose at an annual rate of 13.2 per cent.

Since 1979, fresh fruit has tripled in price, fish has more than doubled, along with restaurant meals, movie tickets, bread, automobiles and shoes. A frequent refrain among middle-class renchmen is that they do not understand how most of their countrymen make do with a median salary of about $500 monthly at last report. The statistics show that Paris is now more expensive thatn New York.

As the pro-Socialist newspaper Le Matin Put it, "It is likely that if the unity of the left had not been broken, for a long interval at least, the prime minister would not have taken the risk of making the shopkeepers unhappy and, to a lesser extent, the farmres. But certain of the loyalty of that electorate, he is now seeking to reconquer ground occupied by the 80 per cent of the voters who are salaried or not working."

How those voters will react is uncertain. In the words of Claude Villain, the government's price director, "The workers have the right to eat a croissant in the morning with their cafe au lait . . . Those products are not superfluous in our time."

The question is how grateful the workers will be to the government if the bakers reufse to make croissants at all. The leftist weekly Nouvel Observateur recalled that Marie Antoinette's famous remark, "If they don't have bread, let them eat cake," represents just one of many instances when Frenchmen mounted the barricades over bakers' prices.

This time, however, Frenchmen seem divided between the temptation to laugh at the mounting tide of witticisms about [WORD ILLEGIBLE] guerre du croissant or to be angry over the blows to their breadbaskets from the two adversaries in a war that has superseded France's other troubles.