PARIS -- Andre Agassi is bored with his tennis clothes. Maybe the look is getting a little old, the hot pink slashes across his shirt and the bicycle leggings, so Agassi will debut a new shade later this year called "hot lava." Agassi is very concerned with style, from his two-toned hair to his stubbled adolescent chin.

Agassi's absurdly teen-hip behavior has been constantly debated at the French Open these past two weeks. Over the last few days at Stade Roland Garros, he smashed two rackets, called French Tennis Federation President Philippe Chatrier a "bozo," and flung a sweaty shirt into the stands. He also began a sentence with, "I was washing one of my cars . . . ." They are impulsive acts committed without apology, with little discernment between the flashy and the trashy, and all in the name of individuality.

"I want the freedom to be what I want to be," he said.

So is the 20-year-old Agassi a genuine individualist, or is he a self-important little monster?

"He's just Andre Agassi," said his agent, Bill Shelton, of International Management Group. He is also this: He has an entourage of six who sport black shades indoors. He refuses to play Wimbledon. He insults opponents and officials with a casual rudeness that is sometimes inadvertent and sometimes not.

He has threatened to boycott the French if Chatrier follows up on a threat to adopt a predominantly white clothing rule similar to the All-England Club's, which provoked the "bozo" remark. He disparaged his U.S. Davis Cup captain, Tom Gorman, suggesting he be replaced, and refused to play a match against Czechoslovakia this winter because Gorman did not want his entourage present.

He has risen from the night neons of Las Vegas that turn dusty in the light of day. He's a heavy-metal trendsetter who brings needed star quality to a staid game that has few remarkable personalities beyond the top three players in the world, Ivan Lendl, Boris Becker and Stefan Edberg.

Discretion is not one of his traits.

"No, not really," he said. "I have never been a pushover. I don't plan to bend. . . . I will make a statement. I'm willing to make a stand."

If nothing else, fifth-ranked Agassi lends some badly needed interest to the men's side of the French Open, with Lendl absent to better prepare for Wimbledon and Becker and Edberg victims of first-round upsets. Each day, throngs of teenagers besiege the Nike sporting wear booth clamoring for his poster. And Agassi also poses the most compelling question of the four semifinalists: Can he win his first Grand Slam title and put to rest nagging criticisms that he is too much the showoff and too little a champion?Added Dimension

He is the highest seed left at No. 3. His opponent Thursday will be unseeded Jonas Svensson of Sweden, and Agassi is very much a favorite. No. 4 Andres Gomez of Ecuador meets No. 7 Thomas Muster of Austria in the other match. Agassi claims he will bring a new physical maturity to his fourth attempt to reach a Grand Slam final, far thicker in the chest and legs than he has been, and a more subtle inner growth as well.

"This is the only time I've gotten to the semifinals and felt like I want more," he said. "In the past I've been satisfied about it. I am by no means satisfied with this performance."

Agassi's chances depend largely on just how much he has matured in the last turbulent year. In 1988 he rose to prominence as an 18-year-old by winning six singles titles, making the semifinals of the French and U.S. Opens and becoming No. 3 in the world. He also garnered screams and fainting spells from young girls, with his mane of blond-on-black hair falling down his back, and his various stunts and histrionics, very much the son of a Las Vegas showmaster named Mike.

But in 1989 he had a far less promising match record of 41-19 and won just one tournament. Only a late surge and semifinal appearance at the U.S. Open kept him from plummeting out of the top 10, ending the year at No. 7. He grappled with his success and with a switch from a Prince racket to a Donnay. He was so unhappy with his game that he tried to revert to his old racket. He used a badly disguised model and got caught, causing some embarrassment. His decision to skip Wimbledon yet again -- he will not play this year either, his lone appearance a first-round loss in 1987 -- drew harsh criticism from tennis observers everywhere.

He also showed a certain lack of effort. He lost a five-set match to Becker in the Davis Cup after leading, two sets to none. He lost in the third round of the French last year to Jim Courier, another young U.S. prospect who, like Agassi, trains at Nick Bollettieri's tennis academy in Bradenton, Fla. That upset was most symptomatic of his entire year, inconsistent on the court and erratic off it.

"Last year I had a plane reservation after every match, just in case," he said. "This year I packed two weeks worth of socks. That's the difference in attitude."

Agassi put on slabs of muscle with the help of his latest addition to the entourage, University of Nevada-Las Vegas strength coach Gil Reyes. New endurance has made him more patient in his shot-making, building points rather than the scatter-shot cannon he was previously, relying largely on an ax-like forehand. He dispatched defending champion Michael Chang with something approaching ease in the quarterfinals. The two most prominent young Americans have similar games; the difference between them was Agassi's strength and new intelligence.

"I think he's picking his shots better," Chang said. "He doesn't give you a lot of time to recover, you're always on the run. He's learning when to hit hard and when to be patient."

As his bird-like chest and legs have filled out, so has his internal fortitude. Against Mats Wilander of Sweden here two years ago, he went five sets only to lose the last one, 6-0. He admitted this week, "I thought of bed and getting off the court quick." He also flagged in his only other semifinal Grand Slam matches, two losses to Lendl at the U.S. Open in '88 and '89. He seems less prone to let sets go before they are lost, one old habit that brought on the quitting comments.

"Now that I'm more physically capable it allows me not to panic," he said. "I can go for the shot I want. I'm seeing more clearly what I want to accomplish out there."

The 18-year-old Chang's victory last year had a certain influence. After losing to Courier he had to go home and watch a younger player (Chang) do what he was not capable of: defeating Lendl in the round of 16 and Edberg in the final.

"I said, 'Wow, I couldn't have done that,' because of the way he did it," Agassi said. "The thought of him winning made me think I could have a shot at it."Growing Up, Coming Back

Those near to Agassi maintain that last year's troubles were a typical sophomore slump many players experience after a breakthrough. Bollettieri has long insisted that Agassi would be brought along slowly, unlike previous proteges Jimmy Arias and Aaron Krickstein, who suffered injuries and showed signs of burnout. Shelton called it a year of overall adjustment.

"We all grow," he said. "If we think we know everything and we don't want to learn, then we don't get better. I think he continues to grow. He was just going through a learning process."

But sometimes Agassi has an irritating way of knowing everything. His public finger-wagging at Gorman lacked grace, particularly since he had skipped a team meeting the night before his remarks, in which Gorman had offered all participants the opportunity to sound off. "If he had been there he could have said it privately," Gorman said, refusing to comment further. His continual refusal to play Wimbledon is inexplicable: He has cited annual fatigue, the wish to play a light schedule at that time of year and the fact that he doesn't consider it as important a tournament as the U.S. Open.

Nor is he easily argued out of his stances. "Don't make me answer that question again," he snapped when asked about Wimbledon earlier this week. Of the Gorman feud, he maintains the captain takes the fun out of playing. He has left open his Davis Cup future.

His sense of style is also unbending. Agassi considers his attire and behavior all part of his one-man crusade to make tennis fun. If you differ with his taste, you can't argue his obvious fan appeal. And if he often flouts authority and convention, he doesn't advocate total anarchy. "There should be some lines," he acknowleged. Perhaps Agassi himself summed up the delicate line he tries to walk and frequently strays from.

"If you only wear flashy clothes and you can't play then it doesn't work," he said. "You need both. It isn't just clothes that make people like you. But it adds something. Just ask the people."