Two of the top designers here are having a little fun at the fashion industry's expense - by staging takeoffs on the clothes coming down the runways this week.

The first flight of fancy took off Sunday night, when Japanese-born Paris designer Kenzo Takada brought the look of Mickey and Minnie Mouse, Bugs Bunny and various teddy bears to his jam-packed showing in his Place Victoire house.

Kenzo, who dressed up as Mickey Mouse for his 40th birthday party at La Palace recently, intended his showing of "comic-strip" clothes to poke fun at the pretentiousness of his colleagues and the "couturier-than-thou" quality of their designs.

But it is hardly all fun and games: Pare away the accessories and the stage makeup, cut out the antics, and, according to several buyers, his designs are some of the most wearable clothes around.

"They are just fun, pretty and very wearable," said Ellin Saltzman of Saks Fifth Avenue, singling out the knit dresses, including the Minnie Mouse style - minus thecostume details, the long low-slung jackets in plaids and stripes and the organdy blouses with pointed bibs.

Karl Lagerfeld of Chloe also intended details in his show to satirize the theatrics of his designer colleagues. Like Claude Montana, for example, he opened his show to a loud opera overture. But no Wagner for Lagerfeld: His opera choice was Scott Joplin's "Treemonisha" ("No one knows this music in France," said Lagerfeld, who got the record as a gift from a friend and loves it). But he quickly switched to some snappy disco numbers, because "It is necessary to have music the girls can walk quickly to, not music to put the models and the audience to sleep."

It was Lagerfeld who singlehandedly launched the shapely look in Paris six months ago. "Women have gotten too sloppy in loose, oversized clothes. They've become too careless about themselves and they are no longer attractive," he said at that time, when he introdued tight torsos, and foam-padded strapless "bustiers" tops, and revived, in a modern way, the peplum suit with the narrow skirt. Both of these styles have been roundly copied on both sides of the Atlantic.

Now he has taken shapeliness one step further, rounding out the sleeve. Sometimes he uses padding to get the croissant or horn-of-plenty shaping, other times it works by the construction of the garment. Whichever way, it has the advantage of making the rest of the body look small by contrast. His bustiers now are available only on evening dresses or suits.

Lagerfeld's knits are light-years in price and attitude from those by Kenzo Takada. But like Kenzo's, most are nifty, simple chemises, coat dresses, peplum suits, sweaters and coats-once the accessories are removed. His narrow wool coat shapes, some with details reminiscent of Balenciaga, are bound to be copied by American manufacturers-and may make them a lot of money.

Lagerfeld has put aside the powedered wig, wing collar and smock he usually wears in favor of a green tweed jacket and four-in-hand tie. But there is still a sense of history in his collection. So when the knits and the smashing coats were finished-including some leathers and some velvet evening suits-out came a remarkable collection of evening clothes: embroidered dresses and coats ("it's one of the things the French can still do well,") geometrically-shaped lace trim on dresses, and-would you believe bustles and trains?

While many buyers put down their pencils after the knits, the coats and suits, Benita Downing of Neiman-Marcus couldn't stop raving. "Those evening dresses are beautifully engineered with great workmanship," she said. "We've got customers who really appreciate this kind of quality and are willing to pay the price. So if it sells, that's all that counts." Even the bustles will sell, she's convinced.

A note about the Chloe accessories, which are bound to count a little less this season: Lagerfeld loves those huge face-framing, fan-shaped hats that show off the forehead hats that show off the forehead. "They show the perfect mask of a woman's face. Even if the face isn't perfect," he insists.

Lagerfeld also likes those knee-high "spats," as he calls them. But any Chloe customer who was a rich kid in a big northern city in the '30s and '40s is likely to remember them as the leggings mummy made her wear on cold days. They weren't much fun then-and aren't likely to be now, either. CAPTION: Picture, Karl Lagerfeld's knit dress with leggings and a fan-shaped hat, left, and Kenzos "Minnie Mouse' look; UPI photos