It is an hour before the showing of Paris new wave designer Claude Montana and already more than 100 people are pushing against the guards in front of the Pavillon Gabriel where the presentation of spring clothes will take place. It's raining and a few umbrellas go up so the rain drains off into notebooks, camera cases and down coats.

The crowd swells as the audience from an earlier fashion show reaches the steps of the building and the pushing begins. Buyers, press and friends of the designer all have invitations to see the show. Finally, at the exact hour the show is scheduled to begin, the door is opened letting five or so ticket holders at a time ooze past the guards.

There are 700 chairs inside, a number of them already filled by those who have made it through the bushes to the back door. Eventually about a thousand get into the show. The rest move angrily from the steps.Among the 400 or so rejects: Women's Wear Daily, Vogue magazine and Lord and Taylor.

It is Indian summer in Paris and time for the twice-annual ritual of viewing and buying French ready-to-wear, this round of clothes to be in the stores for next spring. It is hard to know exactly how many buyers and press are here from all over the world since the organization is haphazard, and unaffili ted and often nonaccredited individuals greatly swell the number of people attending the shows to view the clothes. Some are guessing 50,000.

If the French are lax about who gets into the marathon showings all over town and into the exhibition hall at the Prote de Versailles, they have little trouble keeping count of the increasing amount of business. One reliable estimate puts the amount of French clothing bought by Americans at $50 million of the total $1.5 billion mass-produced fashion business here. American business with the French is up a third from the year before, says a report of the ready-to-wear organization.

This is the 20th year of the Pret A Porter show but no one is being very sentimental about it mainly because few have time at this moment for such things and the form of the shows and the talents involved have changed so since the first exposition in a temporary building in 1957. Even now the coliseum-like Porte de Versaile is almost too small for the 1.125 exhibitors.

Daniel Hechter and Jean Cacharel were among the first to understand mass produced fashionable and modern clothing while the grand names of couture like Dior and Givenchy were making one-of-a-kind designs for the rich and the royal and inspiring the dressmakers that garbed many French women who wanted fashion looks without couture prices.

Madame Gres was the first of the couturiers to understand mass produced clothes and started designing them in 1959, but quit after two years. Others got on the bandwagon in 1961 but only in 1967 did Saint Laurent open the most continually successful ready to wear. It gaves his name worldwide recognition through boutiques and licensing that now brings him $200 million in business annually.

Currently the established names like Saint Laurent, Kenzo and Dior get all the press and much of the money from buyers, but many of the new ideas come from the New Wave designers, newcomers who were peddling their designs at booths at the Porte de Versailles two years ago and now have the most jam-packed shows in Paris. Claude Montana, Thierry Mugler, France Andrvie, Anne Marie Beretta, Jean Claude de Luca, hardly names with a familiar ring like Cardin or Chanel, but clearly the current "Hot" talents here.

Japanese model and Paris fashion star Sayoko says she wears the clothes of Saint Laurent and Lagerfeld for their influence. Kenzo, Myake and Kansai Yamomoto for the local color, and Claude Montana and Thierry Mugler for the future. They may be unknown now, but she picks them as the wave of the future.

As in the United States, women designers with the exception of Chanel, have never been the big names. But that is changing too. Sonia Rykiel is one of the current "biggies" with her easily recognizable supple knit costumes and does about $20 million in sales, a little more than half of that in exports.

But along with Rykiel, Andrevie and Beretta, Christine Bailly, Dorothee Bis, Viviane Viterbo and Elizabeth de Senneville are significant talents in the ready-to-wear scene here.

Says Agnes B., the stylist with her own successful boutique in the Les Halles area, "Every morning when I get dressed I am thinking about new designs. (Agnes B. uses only a last initial, having dropped the rest of the name for her ex-husband Christian Bourgois.)

So far there have been few dramatic changes or innovations in the clothes being shown, though styles range from baby rompers to monks' rubes and Marlon Brando leather jackets. Everthing is very big - jackets, dresses, skirts, blousons, vests, sweaters, tunic, coats, even ties. Things look so big in fact, that it appears as if you borrowed your boy friend's jacket or vest. But that is the way things have been going at home. Big dresses are selling, so are all the blousons. These collections will give buyers and manufacturers the assurance to keep making these clothes and making them bigger. And often more broad-shouldered.

Everything is lighweight, unconstructed and layered. Starting with the shortest garment. the levels of layering at France Andrevie, for example, build up like this: a vest over a jacket over a tunic over a big skirt over a pair of pants. Wear it all or any combination of parts.

Many of the clothes are cotton, in bantam weights so that they are as un-bulky in all their layers, as cool for hot weather, as see-through and sexy as big and blousy clothes can possibly be.

Often the different pieces of clothing are different colors, in unexpected combinations. Khaki shows up everywhere, and so does the color of wet sand, plus ecru, saffron, a pretty soft turquoise and a pale sky blue. And lots of white.

Pants are around in every possible length as long as they are not man-tailored but rather soft. They are always baggy at the top, tapered to the ankle. Knee pants and Bermuda shorts and shortalls (short jumpsuits are plentiful and clearly meant for the city since designers are showing them on models with pantyhose and citified shoes and sandals. Remember the playsuit, the skirt over shorts? It is bound to come back, only now the skirt is worn open and hands are pushed in the shorts pocket.

A casual hands-in-the-pocket attitude pervades everything so far. It is all meant to look and feel relaxed and easy whether it is an evening dress or a pair of pegged pants. Adding to the informal look are the tiny knitted caps with rolled brims and all the straw-brimmed styles.

Among the assortment in pants styles are the dhotis and sarouls (moroccan draped pants) both of which look a bit like droppy diapers as they wrap between the legs, harem pants and bloomers of all sorts.

If there is an outside influence it is more "Star Wars" and punk than based on any traditional costume. Fantasy clothes of past years have used up about all the countries for inspiration, and there is no place to go but outer space. Gianni Versace in Milan said his new collection was inspired by Superman and Kubrick's "2001." For others the tone is more "Rocky" horror show and Lord of the Rings.

There is punk influence at Thierry Mugler including a punk model with flourescent yellow hair cut in the manner of David Bowie. There's also a punk-styled editor from Amsterdam with pitch-dyed hair and always dressed in black. And the punks were out in force at Kenzo.

It is a good year for the fat and the pregnant since no clothes are ever too full, yet a better year for the skinny since everything unless well cut in light fabrics - tends to make you look as huge as Versailles even when you are not.

It's a bad year for the button makers and the zippers manufacturers since many things pull over the head or wrap loosely around the body.

It's a bad year for print makers (haven't we all been "printed" to death?" asks designer Karl Lagerfeld), and a great year for the cotton mills, particularly those who can turn out gauze, linen, terry cloth, poplin, organza. Of course there are exceptions such as Ungaro whose prints are a signature.

T-shirt makers are in trouble because T-shirts are back to square one, being the botton layer, what you wear under everything else, if you wear them at all. Summer sweaters take their place.

Tailors are in for tougher times not only because nothing is ever too big or even too small since you can always hide something big over it, or too long or too short, but if you want to change the length, say, of pants, you simply roll up a cuff and let the seams show.And if sleeves are too long you push them up on jackets, blouses, skirts, dresses - whatever. (Even if they fit perfectly you push them up.)

Rooms are always filled to capacity and Friday night the nightmare that almost evryone fears at the pret A Porter showings nearly took place. Before the end of the Suzuya show, smoke started circling into the spotlight beams and the smell of fire was evident. Chairs were pushed over, several cameras leveled as editors and buyers pushed to the open doors to the terrace. One foreign buyer fainted buy reportedly was simply carried along by the crush on her feet.

"Never again, Never again," shouted one American woman as hse searched for her papers in the darkened room. "It's not so bad," answered her companion. "It will give us a head start getting to the next show."