In years past, the French paid relatively little attention to their homes, preferring instead to spend much of their time in cafes.

These days, however, they want comfortable houses and apartments, and their demand for dwellings has touched off a real estate boom of unprecedented proportions.

Here, as in the United States, real estate prices and rentals have skyrocketted, so that suitable accommodations are available either to the rich or to those willing to sink deeply into debt.

This phenomenon reflects a drastic change in the conduct of the French. Formerly, the most significant item in their budget was food. But now they are allocating a large and larger percentage of their incomes to housing.

Condominiums in Paris currently sell on the average for the equivalent of $75 per square foot, which means that an undistinguished four-room apartment can cost about $200,000. The same apartment is likely to rent for $1,200 per month -- which is not much less than the average monthly income for a Persian family.

Real estate in the provinces is generally cheaper, but there are exceptions.

In Cannes, on the Riviera, luxury apartments are going for as high as $7,500 per square foot. A three-bedroom apartment, therefore, runs to more than $1 million.

I thought I was being extravagant in 1968, when I paid $70,000 for a rather modest apartment in a pleasant but not very fashionable Paris neighborhood. The apartment, which has nearly tripled in value since then, would be beyond my reach today.

At the time I bought the apartment moreover, I made a down payment of $35,000 and took out a $35,000 mortgage. Today, for the same apartment, a buyer would have to put down at least 20 percent, or $55,000, and carry a $150,000 mortgage -- far more than anyone in my income bracket could afford.

Add to the spiraling prices the fact that the costs involved in owning real estate have soared. Between 1974 and 1978, for example, the cost of central heating has gone up by 46 percent.

But the rush to acquire houses and apartment continues unabted, in part as a hedge against inflation. In short, the French are investing in real estate for the same reason that they are buying gold.

Even though it is more visible than gold, real estate is a shelter as well for money earned in various shady ways, such as moonlighting and tax dodging. It offers fiscal advantages, too, since the interest on mortgages is deductible from income taxes.

The boom also owes its dynamism to the fact that, within recent years, Paris has been torn apart, either to make way for new buildings or for the renovation of old ones. The result has been a real estate speculator's dream. r

Entire districts, once composed of little ateliers and shops, have been razed in order to construct skyscrapers, so that the formerly graceful horizan of this city has become as angular as that of Manhattan.

Meanwhile, sections of Paris that were deemed of special historic interest have been preserved -- but their ancient buildings have been remodeled and put on the market with outrageous price tags.

One effect of this development has been to empty Paris of its middle-class citizens, whose pocketbooks are not fat enough to deal with the boom. They are migrating to the suburbs. As a consequence, the inner city's population has dropped by about 300,000 over the past five years, and it is expected to dwindle further.

About half the present population of about 2 million consists of low-income residents, like craftsmen, office employes and service personnel, who have been able to remain in the city because they occupy rent-controlled dwellings.

But controls, which were imposed in 1948, have been gradually coming off as the result of legislation passed six years ago. This will spur the poor to leave the city, and it will also stimulate the speculators to demolish or revamp the buildings they quit.

The very poor may not suffer seriously, since they can apply for public housing. Nor will the wealthy, who have the means to buy fancy real estate. The middle classes, however, are certain to be caught in the crunch.

So will the younger generation, which aspires to better housing than that accepted by their parents. According to a recent survey, 71 percent of those between the ages of 18 and 25 hope to own houses or apartments eventually, and that hope tops their list of priorities.

"Futurologists" here believe that the current turmoil will persist for another 20 years before it stablizies. At that stage, one urban specialist predicts, Paris will have become a "privileged city" of open spaces, efficient services and first-rate housing.

But judging from the transformation of its population, brought about by the real estate frenzy, Paris two decades from now may well be a city of the privileged.