Hugh Capet was crowned king in 987 and the French now look on that date as the birth of France. The country is celebrating the end of its first millennium with religious ceremonies, sound-and-light shows, medieval jousting tournaments, historical symposiums, a bit of monarchist nostalgia and souvenir bric-a-brac decorated with 1,000-year-old designs.

There are historical problems; nobody knows much about Hugh Capet. No scholar has ever been able to find a single medieval drawing or written description of him. His kingdom was not much, no more than bits of royal domain around Paris. He was probably more of a kinglet than a king. It is not even clear what he did as monarch aside from persuading a Roman Catholic archbishop to sanctify his son as unchallenged heir to the throne.

Hugh Capet’s only hold on French memory is biological. He founded a dynasty of kings unbroken until the revolutionaries decapitated King Louis XVI in 1793. The king’s birth line was so clear that his tormentors insulted him by referring to him as Louis Capet, not King Louis, before dispatching him to the guillotine.

So little attention is usually paid to Capet, in fact, that some skeptics believe the celebration of the millennium is no more than a sop to right-wingers angry about the coming celebration of the bicentennial, in 1989, of the bloody French Revolution.

Yet the 1,000th anniversary, whether real or confected, has made the French introspective. There is a boomlet in books on French history this year; newspapers and newsmagazines brim with exposes of the soul of France. What is a Frenchman? Are the French lazy? Are they rude? Is France in decline? Is it racist? A millennium is obviously time enough to take stock.

“The Identity of France,” a posthumous book by the reknowned French historian Fernand Braudel, has been a best-seller throughout the year. “The word (identity) seduced me,” Braudel wrote, “but it never ceased for years and years to haunt me.”

In this millennium year, other French historians have also been seduced and haunted by identity. These historians have reached two main conclusions that seem contradictory but are really not: They agree, first, that French culture, whatever it is, has enormous power to assimilate foreigners, easily and relentlessly, and, second, that the French society sustaining this culture has long been rent by ideological and social cleavage.

The attempt at assimilation is total. Despite all the snickering from outsiders, French teachers still make their young pupils, no matter how African or Asian in origin, read a textbook that begins, “Our ancestors, the Gauls . . . . “

“I see nothing absurd,” historian Jean Tulard wrote recently, “in teaching our little North Africans in France that their ancestors are now also the Gauls and that from now on they carry on a very long history.”

That long history, however, is rent with strife and hatred. Historian Pierre Chaunu recently wrote that the unity of France depends on having two kinds of people opposed to each other. At least since the French Revolution, French republicans and monarchists and then leftists and rightists have treated each other with contempt and bitterness.

“France needs a permanent civil war,” Chaunu wrote, “and we have the genius to revive it as soon as it is in danger of going out by itself.”

Other historians, however, believe that the permanent civil war is coming to an end, that France must be defined differently now.

The intense concern with identity has come at a time of festering debate over immigrants. More than 5 million foreigners or naturalized immigrants live in France, 10% of the total population. Many are North Africans whose strong Muslim faith makes them seem difficult to assimilate. Even Braudel wrote that the mosques of France vexed him as “the symbol of rejected assimilation.”

Increases in unemployment and crime have come in the wake of immigration and many French have made North Africans the obvious scapegoats. The discontent has been fanned by Jean Marie Le Pen, the extreme right-wing leader whose party took more than 10% of the vote in the last legislative elections.

To muffle some of this thunder, Premier Jacques Chirac, the conservative leader who came to power in 1986, was determined to show that he, too, could be tough on immigrants.

Chirac wanted to revise the code of nationality so that a child born in France of foreign parents would not receive citizenship automatically but would have to enter a court at age 18 and ask for it. Unless he was a criminal, he would get citizenship, but he still had to take the positive step of seeking it.

Then revision of the code became a symbol of discord and French citizens are no longer in the mood for discord. Chirac found that although the diatribes of Le Pen appealed to some French, many more listened to the reasonable, anti-racist ideas of 27-year-old Harlem Desir, a dynamic leader of French and Caribbean descent who heads a popular organization called SOS Racism. Even if many French were irritated by immigrants, most did not want a conflict over them. The French were far prouder of Desir than of the sporadic, ugly racial attacks in large cities.

Chirac, trying to retreat gracefully, asked 16 “wise men” to study the code of nationality and then announced in early September that he would make no code changes before the next presidential election in 1988 unless he could find a “national consensus” to support them. No one expects him to find it.

The retreat meant that Chirac has discovered belatedly what many analysts have been insisting with all their introspective analyses of French society: Divisive forces still trouble France but most French are tired of the old battles, the old lineups and the old ideologies. The people have never felt so at ease with each other.

It is not clear why France, which once nurtured some of the fiercest-held ideologies in the world, no longer feels ideological. Many analysts attribute it to the growing and belated intellectual disillusion with the Soviet Union in the last two decades, the quick realization by the Socialists that they could not really change France radically after taking power in 1981 and an economy that is reducing the differences between the haves and have-nots. But whatever the causes, there is no doubt that the French are more concerned with pragmatism than ever before and more tolerant of the differences among them.

Pierre Nora, a French historian, has written that the French are discovering “the depths and roots of their national phenomenon” with a “curiosity for the richness and diversity of its expressions.”

“It is as if,” he went on, “France has ceased to be a history that divides us to become a culture that brings us together.”

That is the lesson from introspection during this year of the millennium. Politicians who understand this best will probably profit from it most in the presidential election of 1988 and the legislative elections that may follow soon afterward. Some commentators fret that this will make their politicians worry far more about their look than their ideology. But perhaps that is the price a people must pay to begin their second millennium more united than ever before.