Ask the French if they are satisfied with their lives, and they will invariably gripe about everything from high taxes to low incomes. But, in a curious way, their lifestyle contradicts their complaints.

For the French, perhaps more than any other people, are masters at circumventing the system. So, while official statistics show them to be relatively deprived economically, they manage through a variety of legal loopholes to lead quite a comfortable existence.

Thus the real wealth of France seems to me to be vastly underestimated - which is another way of saying that the French are far better off than they will ever admit.

According to official figures, for example, French wages are ppaltry. An average worker earns the equivalent of $450 per month, and the salary of a senior executive rarely exceeds $20,000 per year. The assets of the French are estimated at $4,000 per person - barley suficient to produce additional income.

Meanwhile, the inflation rate here has been running at close to the doubledigit level, and unemployment is reaching crisis proportions, largely as a result of a new austerity program initiated by President Valery Giscard d'Estaing and Premier Raymond Barre.

But with all this, the traffic jams in Paris and the other cities of France are testimony to the fact that 70 percent of French families own one automobile and 20 percent possess two cars. At least 10 percent have second houses in the country, and many spenend lavishly on food and leisure.

Paris restaurants, which are hardly cheap, are always jammed. During the past Christmas season, the French consumed 50 million bottles of champagne. More than a million went skiing at winter resorts or sunbathing in warmer climates. Half the country regularly goes on vacation in the summer.

Therefore, since they are unaccustomed to using credit cards, the French have other ways of getting by than relying on their incomes. One is by taking advantage of the government's generosity. The other is by maneuvering through a maze of rules and regulations.

The government is France's largest philanthropic institution. It augments salaries with family allowances and a wide range of other benefits including free medical care, education through college and even cut-rate funerals.

The proliferation of day-care centers makes it possible for mothers to work, and they contribut significantly to family incomes. At the same time, both government and private enterprises furnish their employees with special privileges.

The nationalized electricity company, for example, charges its workers lower energy rates, and railway employees and their families travel at reduced cost. Many firms sell their own products to employees at discounts that vary from 15 percent for cars to 35 percent for color-television sets.Banks lend money to their staffs at 3 percent, compared with 15 percent for others.

Numbers of French company directors, civil servants, school teachers and others are given dwellings among their perquisites. Many firms have summer villas, vacation centers and children's camps for the employees. (KEY OFF) rivate (KEYWORD) French firms own some 300,000 automobiles for use by their executives, usually with chauffeurs. Most of these executives take company cars on vacation, usually without chauffeurs. Senior bureaucrats also drive government vehicles for pleasure.

Certain government employees are permitted as well to increase their incomes through legal kikback arragements. Mortgage registrars, for instance, take a percentage of each transaction. Government engineers also get bonuses calibrated to the value of their projects to keep them from shifting to private companies.

Then there is, as in the United States, the executive expenses account, without which 80 percent of Paris restaurants would slide into bankruptcy. The tax authorities monitor expense accounts, and they tend to be tolerant.

But the padded expense account is a mild form of tax evasion for the French. Ordinary wage-earners cannot cheat, since their taxes are deducted from their paycheckss. However, fraud is widespread among doctors, lawyers, shopkeepers, artisans and others in independent occupations - so much so that tax inspectors base assessments on so-called "exterior signs of wealth," such as ownership of a deluxe apartment or membership in a golf club.

One of the more humane features of this approach is that tax dodgers are rarely jaied, but can bargain a compromise with the fiscal authorities. Farmers, who are notable tax evaders, are constantly negotiating.

Moonlighting, which is becoming more and more frequent here, is another way to avoid taxes, since its practitioners do not declare their afterhours earnings. Estimates are that moonlighting now accounts for about 10 percent of the national income. Or put differently, it represents some $10 billion in labor, which, if legally performed, would funnel millions into the government treasury.

Roughly a million French men and women moonlight in the evenings or on weekends. Cops double as janitors, firemen as plumbers, and assorted others perform unreported sideline jobs on which they make money and side-step taxes. Many unemployed also work covertly, thereby receiving wages as well as jobless compensation.

From a social point of view, all this hustling is reprehensible. For it drains the country's economy of incalculable sumes, compelling the government to depend for revenue on indirect taxes, which are inequitable.

But it explains the extraordinary ability of the French to eat, drink and be merry amid economic troubles, and it underlines their fundmental prosperity despite their chronic grumbling.