Twenty years ago at noon, France's last war ended. But not a single monument commemorates the end of the Algerian conflict.

No argument rages in France similar to that anguished debate in the United States over the Indochina conflict and the current controversy on the memorial to America's Vietnam War dead.

Indeed, only a brief scuffle tonight at the Tomb of the Unknown Soldiers here recalled the violent passions that the nearly eight-year Algerian War aroused on both sides of the Mediterranean.

The French--despite a spate of newspaper and magazine articles and television documentaries marking the anniversary--have decided long ago to forget the Algerian War.

The brief violence today--pitting protesters against a veterans' group lighting anew the flame honoring France's unknown soldiers--was a throwback to other, more serious confrontations along the Champs Elysees when the fate of France hung in the balance.

Yet the thought of formally celebrating the accords of Evian ending the war remains anathema to the die-hard core of French settlers and career Army officers who had sworn to keep Algeria French.

Last fall a purely political argument flared when the opposition bridled at the Socialist government's suggestion that the Evian accords should be officially commemorated.

President Francois Mitterrand wiped his hands of the scheme (as interior minister soon after the war broke out, Mitterrand had said the French response to proposals for negotiations would be more fighting). After the Evian accords were signed, an orgy of killing by the pro-settler Secret Army Organization in the 3 1/2 months before Algeria's independence became official wiped out whatever remaining chance the million French residents in Algeria had of staying on in what for 130 years had been part of France.

But in retrospect, it is easy enough to understand why the French decided to block out the Algerian War.

France in 1962 had been at war since 1939, losing against the Germans in 1940, losing thereafter in Lebanon, Syria, Indochina, Tunisia and Morocco.

Much to the surprise of those who had warned that mainland France could never provide a living for the million settlers, their mass exodus in the spring and summer of 1962 touched off a golden age of prosperity.

The hard-working pieds noirs--or black feet--as the settlers were called, provided the manpower that fueled the economic boom of the 1960s and 1970s. The fears that the pieds noirs would become a destabilizing political force in France never materialized.

Diplomatically, France shorn of Algeria, returned under president Charles de Gaulle to its traditional policy of friendship with the Arabs--much to the chagrin of Israel and the 200,000 Algerian Jews who had lived peacefully alongside their Arab neighbors until emigrating to France.

At times it almost seemed that were it not for a spiteful small group of settlers and Army officers, the Algerian War might as well never have taken place. Yet by disinterested accounts the war cost the lives of 17,000 French and 245,000 Algerians. Accounts in Algiers put the figures at 30,000 French troops and a million or more Algerian Moslems killed.

The aftermath of the Algerian conflict is not entirely a success story. If the settlers have done remarkably well here, the same cannot be said for the harkis--Moslem troops who fought for France and then were brought here to preserve them from the fate of thousands massacred by the triumphant Algerian nationalists after Evian.

Hundreds of thousands of harkis and their children still make up a kind of volatile subproleteriat among the 800,000 Algerians who live and work here.

Perhaps one key to understanding France's seeming amnesia was the skill with which the French government succeeded in keeping films dealing with Algeria off the state television network. In some cases films were banned for commercial distribution.

Dozens of movies have been made in France about the Nazi occupation, but only a few about the Algerian War.

It was only this week that the French government authorized television screening of the Algerian episode in a serial made more than a decade ago and ominously entitled, "Frenchmen, If You Only Knew . . ."