The ultra-modernistic skyscrapers to the west of Paris are a painful reminder to the French of the false hopes of the 1960s.

This huge commercial development, called La Defense, was to be the "French Manhattan." Now, nearly 14 years after it was started, it stands embarrassingly short of its goal. Almost one-sixth of the total space still remains empty.

Originally planned in the heyday of the 1960s building boom, La Defense is suffering the same fate as many of the spectacular plans that went up under the administration of the late President Georges Pompidou. Anxious to prevent Paris from becoming a city of the past, the Pompidou administration tore down old buildings and market places to make way for gigantic new structures.

Now, in leaner years, the demand just isn't there. The grandiose plans of the '60s assumed a level of growth that, with the onslaught of inflation in the early 1970s, just never took place.

The problem is further aggravated now by the uncertain political climate. With the Communist-Socialist alliance leading the government coalition in the polls, business expansion in France has practically ground to a halt.

La Defense isn't alone; a great deal of office space in Paris is currently vacant.

And the miscalculations of the 1960s are by no means confined to Paris.

Perhaps the greatest mistake of all was Fos-sur-Mer, a sleepy little village near Marseilles that a joint government-business venture planned to transform into a bustling industrial zone with a population of a million people. But today, due to the economic slump and to bad management, only 7,500 of the project's 13,750 acres are occupied. And the factories that are there are only operating at 70 per cent capacity.

The euphoric building spree of the 1960s has now cooled. But the problem remains - how to fill what already exists.

In Paris, the problem is primarily one of location. Well-situated buildings in certain parts of central Paris and in the suburb of Neuilly are still sought after, but offices in less choice locations wait to be filled. Few new projects are being undertaken.

A similar decline in construction is occurring in the Paris housing market. While demand for apartments is great, prices are so high and credit so tight that few people can afford to buy. (There are few private homes in Paris; most people live in apartments.)

Prices of old apartments have been driven up as Parisians become more and more interested in the charm of traditional architecture. The once-cheap old sections of the city - the Latin quarter, Ile St. Louis and Les Halles - have become high-value real estate, as rundown, centuries-old buildings are converted into chic apartments.

In the 6th arrondissement not far from St. Germain des Pres, for example, a two-room apartment is being offered at $116,000.

And, on the Ile St. Louis, an apartment overlooking Notre Dame cathedral is valued at $200,000. It cost one-tenth that 15 years ago.

"The prices go up each day. It's like selling oranges at $3 a half dozen. Few people can afford it," said Paul Garboua, commercial director of the construction firm Sefima.

But even in the case of new apartments, prices are high and sales have been declining in recent months. Few new projects are being started, since builders are unwilling to risk constructing more apartments when they know that buyers can't afford the high rates.

The result is a dwindling supply of apartments on the market. Whereas there were approximately 20,000 units for sale last December, the number declined to 16,000 units last May, according to real estate association figures. Earlier forecasts of 38,000 sales in the Paris and neighboring regions for 1977 have been readjusted to between 34,000 and 35,000. Last year there were 40,000 sales.

Part of the problem lies in the government's recent tightening of credit. Whereas French savings banks were offering credit at 11.6 per cent up until the end of March (for amounts under $30,000), buyers now have to pay 14 per cent and more. This hits particularly hard at low-income buyers who borrow often up to 50 per cent of the price of a new apartment.

With prices and credit so high, people in Paris are continuing to rent rather than buy, hoping that the prices will go down.

The strong possibility that the leftist alliance may win the March elections also appears to be having a slowing effect on the housing market.

"This is definitely having a psychological effect on people thinking of buying," said Bernard Vallet, a spokesman for FNIAM, a national association of real estate agencies. "The uncertainty of the situation makes people unwilling to invest. They go to the agenceis to inquire, but they stop short of making a move."

This hesitation to invest is reflected in the recent slackening in the market for vacation homes on the Cote d'Azur. Although the demand there remains strong, there has been a slight decline since last spring. Construction continues, but real estate agents are reserved about the prospects for the coming months.

Prices there remain high however. Although this strip of Mediterranean coastline has long been expensive prices have climbed dramatically in the past few years. A new two-room apartment in Nice now ranges from $32,000 to $60,000.

Private villas along the coast are in constant demand by wealthy German, Arab, French, English and Italian tourists, despite price tags reaching up into the hundreds of thousands of dollars. For instance, a white stone villa near Monaco with a swimming pool and about two and a half acres of land is currently being offered at $730,000.

To avoid these high prices, some less wealthy vacationeer go further west along the Mediterranean to Languedoc-Roussillon, where a government-business venture has been trying to develop the area for tourism since the 1960s. This coastline, which stretches 124 miles from the delta of the Rhone to the Spanish border, was, until recently, unpalatable for tourists due to its marshy waters, mosquitoes and lack of trees.

Prices on the Languedoc-Roussillon coast are considerable cheaper - about half those along the Cote d'Azur. Yet, despite its lower prices, Languedoc-Roussillon has trouble competing.

"There's an element of snobbism involved," said Jean-Claude Bonhomme, director of Mediterranee Immobiliere, a magazine dealing with the real estate market in the south of France. "People want to go the chic places, to St. Tropez. They want to be where Bardot is. . . ."