That wonderful institution known as "springtime in Paris" has kept everybody guessing this year. After two weeks of steady rain, it finally made a spectacular entry about a week ago, plunging the city into a blaze of life and color--only to disappear back into the clouds two days later.

The erratic weather is, in a way, symbolic of the uncertain political mood as the French brace for what promises to be a period of economic turbulence. The death throes of winter coincided with the third devaluation of the franc since the Socialists came to power in May 1981, a somewhat phony government crisis that was resolved by the appointment of outgoing Prime Minister Pierre Mauroy to succeed himself, and a package of austerity measures that could result in the most significant drop in average living standards since World War II.

With the coming of spring, all these problems seem to have receded into proper perspective. Sated with an orgy of grumbling about currency restrictions and higher taxes, Parisians have turned their attention to what they are best at: the art of enjoying everyday life. It is an annual rediscovery that comes with the first stroll through Paris on a warm sunlit day after the bleakness of winter.

This year, spring arrived suddenly and unannounced. One day there was so much rain that the road along the River Seine was flooded. The next day, most of the trees and flowers in Paris seemed to bloom at once, as if they had been waiting for the first ray of spring sunshine.

Equally suddenly, people began living out in the streets again. Cafes and restaurants spread out onto the pavement, and clients whiled away the hours slowly sipping wine and watching pretty women and handsome men walk by. Bicyclists and roller skaters weaved in and out of the cars backed up along the Champs Elysee, and tourists sat to have their portraits drawn in the twisting streets of the Left Bank.

"The weather is infinitely more important than politics," said a French journalist, leaning happily over a glass of pastis. Just a few days earlier, he had predicted that the growing economic strains could result in widespread labor unrest.

And there lies the paradox of the spring of 1983. The government is widely accused of mishandling the economy, and there is very real concern--particularly among young people--about unemployment and inflation. But, despite all these problems and France's history of violent protests, there is little sense of imminent political upheaval in the air.

The change in mood was illustrated by a recent poll published by a left-wing magazine, Le Nouvel Observateur, about the attitudes of young people. It showed that--by comparison with previous generations--French teen-agers today are pragmatic, materialistic and surprisingly conformist.

Here is an age group that, 15 years ago, dabbled in revolution and rejected parental values. Yet today, according to the poll, 93 percent of French youth described the family as "very important"--against only 16 percent who used the same description for revolution, which came at the bottom of the poll along with politics and trade unionism.

In fourth place with a "very important" rating of 80 percent--just behind work and love--was travel. This helps explain the furor that erupted here last month when the government imposed currency restrictions that will prevent many people from taking their vacation abroad this summer. Other austerity measures were more severe, but this one was seen as a direct attack on individual liberties.

Far from jolting French youth into revolt, it seems that today's economic uncertainties could be encouraging them in the opposite direction. Concern about unemployment (which 66 percent of French teenagers believe will affect them directly) has coincided with the strengthening of family ties and a new mood of serious-mindedness.

At the same time, there seems to be a recognition that, for all the talk of recession, today's generation is much better off than its predecessors. Le Nouvel Observateur reported that 62 percent of young people thought they would be happier than their parents, against only 9 percent who thought they would be less happy.

Among the springtime rituals associated with Paris are the ready-to-wear fashion collections and the annual publication of the Michelin guide to gourmet cooking. These two events have a considerable impact on what French and foreigners alike would like to wear and eat for the rest of the year if only they could afford the prices. But this year they have also touched off debate about whether France still leads the world in the art of living.

This season, the fashion shows were dominated by a new wave of Japanese designers who appear set on penetrating the western market for clothes in the same way they already have done for cars and video machines. Michelin, meanwhile, struck three of France's most famous restaurants off its three-star list, thus deeming them no longer "worthy of a special journey." To the chagrin of French chefs, no new restaurant was promoted.

Like culture, cuisine and fashion are taken with utmost seriousness in France, and foreigners have to tread delicately when they venture into any discussion of these traditional areas of French excellence. An offhand remark in an American newspaper earlier this year about the dearth of good French novelists provoked a week-long controversy and screaming headlines on the front pages of the Paris press.