Small Tri-Colors and Stars-and-Stripes sprouted among the lacy twines of the great green fern in the entrance hall. The hostess alternated between greeting guests and taking the visitors on obligatory walking tours of the residence. It was a free-swing, mixed grab bag of an open house, celebrating the armistice of the war that was to end all wars.

It was 60 years ago that the word came from a dining car at Rethondes in the forest of Compiegne northeast of Paris that World War I was over. And Saturday evening Ambassador and Mme. Francois de Laboulaye acknowledged that event with a reception at the French Embassy for military men and women from France and the United States. It was not the unusual diplomatic cocktail crowd - nor was it exclusively a gathering of World War I veterans.

If U.S. and French officials find difficulty agreeing on almost anything else, they can indeed come to terms on cooperation during World War I.

France lost almost an entire generation of young men to that war. In recognition of the cooperation and aid from across the ocean, the French billed their party, "merci, pershing." (It was also most likely in recognition of that particular tie that M. de Laboulaye was the only representative of a foreign nation invited to the American ceremonies at Arlington National Cemetery earlier on Saturday.)

In France, Nov. 11 is the legal holiday on which the French people commemorate the armistices ending both wars, and it is also, according to President Valerie Giscard d'Estaing, the day on which "France faithfully keeps alive the memory of all those who died for her."

Fifty French war veterans from both world wars, flown over especially for the American events, contributed to the babble of French and English as they discussed wars past and unrest present and nibbled on sanwiches and miniature quiches. Greeting with the guests, along with the hostess, was her dog, a Scotty, who wagged and bounced at the end of his leash, which was tied to a radiator near the door.

One of the few guests who remember the Great War, 80-year-old Louis Montague, said that the romance and appeal of World War I was that it was "a young man's war," fought at least in part by young idealists who expected it to end in a few months. The last "romantic" war became the first modern war, and millions would either die or be wounded before the armistice four years later.

With a resigned Gallic shrug, one former military officer said that he wasn't "too surprised" when the World War I didn't end all wars but was in fact a prelude to another large war.

Barbara Tuchman and all the history books to the contrary, guests at Saturday's reception maintained that World War II was really the last romantic war. "What could be more romantic than the French resistance?" queried one.

As the Moet et Chandon flowed, so did the conversation, and talk turned to matters of war. The remembrances of a majority present were those of the last and not the first world war.

Said one in reviewing that war, "I am no Gaullist. Nobody loved De Gaulle, but everybody respected him and he was the number one expert in tanks," Noel de Champeourt, former member of the French fourth tank legion noted the reference to tank warfare, and chimed in, "Patton must have been a student of De Gaulle."

D. H. Lawrence, in referring to the disillusionment following World War I, said, "All the great words were canceled out for that generation." And it has been for later generations to pick them up and remember. That is what they were doing at the French Embassy on Saturday when they spoke of more recent wars and the men who died - and lived - and who were being honored.

"Certainment, " said one, "World War I was the last of the old wars. It was a national war and by World War II we were fighting a political war."

"The French were fighting for their own house in both wars," observed another. "And we are grateful to the Americans who helped."