As the battle of the blouson goes on in the garden of the Louvre, a fashion designers' war of big egos and big bucks has heated up and moved out to parties all over the city. The big American retailers, and the press, are being courted.

Italian designer Giorgio Armani came to town with an entourage to introduce his perfume at a bash at the Palais du Chaillot. The day before, Time magazine's cover story on Armani appeared in spite of an April 1 embargo on all pictures of his clothes for fall, which the designer had refused to show formally to the press. Time claimed a "coup" in being first with the pictures. John Fairchild, publisher of the influential fashion paper Women's Wear Daily, cried, "We were deceived." And Armani replied, "It wasn't planned that way." But Time magazine in Rome countered, "It was absolutely clear we could come out with the story a week before now if we wanted."

Most of the store buyers are ducking the fray between designer Armani and publisher Fairchild. "I remember the time when Fairchild came crashing down on Bill Blass," said a U.S. fashion director. "Blass said it hurt his business a lot. Business is tough enough already. I wish this damn thing were over."

Fairchild never got to any of several parties Tuesday night. "I'm sick in bed," he reported. "Someone said I've got the Armani flu."

"Let them eat pa te'" is the watchword as French designers invite select guests to shows and parties in an effort to secure good will from buyers and store presidents. At the Jean-Louis Scherrer show, the audience included a Mitterrand (Robert) and a Giscard (Vale'rie-Anne Giscard d'Estaing). Dior countered a weak show with dinner at Le Train Bleu, one of Paris' currently "in" restaurants. On the same evening, Valentino offered dinner with society hostess Countess Brondolini. Emanuel Ungaro and Bettina Graziani, friend of the late Aly Khan, entertained at Maxim's.

Vittorio Missoni of the Italian knitwear house reached town, but not before being delayed by French customs. He lost three days of selling time, which annoyed him to say the least because he was eager to sell his goods in Paris to American buyers who didn't make it to Milan.

While the French were making their big efforts to counter the competition from the Italians, they opened their doors to a new wave of designers from Japan. Designer Kansai Yamamoto said, "The Japanese designers come to France for the prestige; they go to New York to sell their clothes."

Adding to the firmly entrenched Japanese, particularly Kenzo, Yamamoto and Issey Miyake, at least a half-dozen other Japanese showed their collections under the show tents near the Louvre. "The new Japanese firms don't have the formula for the American figure yet, but before long they'll be giving the French some real competition," said a buying office executive who didn't want to risk being identified by the Japanese as critical of their early efforts.

"This is not a party, this is like a bad time on the Me'tro," said Karl Lagerfeld as he looked at the gridlock crowd gathered for Armani's perfume introduction. More than 5,000 guests passed under a huge black plastic frame in the shape of an Armani bottle to enter the Palais du Chaillot.

Even before the fashion show, which included 12 black evening costumes from Armani's current collection, many guests could find no place to check their coats, and no silver for dinner--if they could get near the buffet. "It's a nightmare," said a New York retailer who could barely turn around to see the show.

When models paraded near a gigantic replica of the Armani bottle, fireworks were set off outside in front of the Eiffel Tower. Officials of rival stores were warning their competition, with good reason, against even trying to enter the crush. "Thank God for the boycott," said Gerard Semhon, president of Helena Rubinstein, who put on the party, referring to John Fairchild's decision to stay away. "We wouldn't have room for another person."

Halfway through dinner at the American Embassy Tuesday night the lights went out, so guests in the tapestry-filled dining rooms had to finish their dinners by candlelight. A few guests who had parked themselves at the top of a marble staircase were without any light at all. "I thought it might add to the intrigue of the different fashion shows ," said Ambassador Evan Galbraith as his wife, Marie Helene ("Bootsie"), dashed through the rooms using a cigarette lighter to light candles that had been tucked away in drawers.

More than 40 of the guests were members of the Smithsonian's National Associates Board, here for the opening of the American Impressionist show at the Petit Palais and the spring meeting of the board. Since it coincided with Paris' fashion shows, Saks-Jandel underwrote the party and contributed to the travel expenses of the exhibit as well. "Maybe you could call us the ready-to-wear department of the Smithsonian," teased Smithsonian secretary S. Dillon Ripley.

Many of the guests, including designers Sonia Rykiel, Emanuel Ungaro, Jean-Louis Scherrer and Bernard Lanvin, had come to the embassy from the Cercle de l'Union Interallie'e, a posh private club next door where Vogue magazine gave a party to kick off an upcoming promotion on France. "I know we had exactly 596 guests," said Vogue's executive editor Barbara McKibbin. "That's the count from the man who always gives me the bills."