QUESTION: How can I gain entrance to fahion shows in Paris? ANSWER: attendance at the big shows presenting the new designs of the Parisian fashion houses is by invitation only.The shows are held for fashion professionals, the press and select regular clients.

The shows take place four times a year, usually in late January and late July for haute couture and late March and late October for ready-to-wear.

Invitations are said to be very hard to get, but you can write to the fashion houses and try to convince them that you are a potential customer for their creations.

After the debut, some concerns have shows at their headquarters with models presenting their fashions to visitors, though there is a trend to using films or videos.

In any case, you must write or call at least several days ahead to attend a showing.

Here is a sampling of fashion houses and what they offer. Unless stated otherwise, the mailing addres for each is 75008 Paris, France. Letters and calls should be directed to Madame la Directrice de la Haute Couture.

Pierre Cardin, 14 Place FrancoisI; telephone visits to live fashion shows must be arranged two or three monthsahead.

Chanel, 31 Rue Cambon, 75001 Paris; Live shows are presented Tuesday and Thursday late September to late October and in February.

Christian Dior, 30 Avenue Montaigne; A film is shown each weekday at 3:30 p.m.

Yves St.-Laurent, 5 Avenue Marceau; A video is shown by appointment.

Emanuel Ungaro, 2 Avenue Montaigne; A video presentation can bne seen by appointment.

Givenchy, 3 Avenue George-V; Fashion shows are presented Tuesday and Thursday from mid-February to the end of April and in September and October.

Guy Larache, 19 Avenue Montaigne; There is a video Tuesday and Thursday at 3 p.m.

Nine Ricci, 39 Avenue Montaigne; For live shows, Tuesday and Thursday at 3 p.m.

Christian Lacroix, 73 Rue du Faubourge St.-Honore; A 30-minute video is presented Tuesday and Thursday at 3 :30 p.m.

You can see free fashion shows in two big department stores. Galeries Lafayette has a special showing for foreign visitors each Wednesday at 11 a.m. and also on Friday March through October. A cocktail is served afterward. Reservations: Printemps has a fashion show at 10 a.m. every Tuesday and, March through October, on Friday; also on Monday, May through September. Reservations, two or three days ahead:

There is one luxury tour, leaving New york Jan. 25, that will include the January haute couture presentations, including Nine Ricci, Givenchy, ungaro, Chanel and viky Tiel. Hotel accommodations for the five-day trip are at Le Bristol and dinners are at Taillevent, Jamin and L'Ambroiserie, all given three stars by Michelin. The cost is $8,800 a person in double occupancy, including round-trip flights on the Concorde. Information: Annemarie Victory Organization, 136 East 64th Street, New york, N.Y. 10021; 212-486-0353.

QUESTION: My husband and I and another couple would like to rent a cottage or villa with house=keeping facilities in Ixtapa-Zihautanejo, Mexico, in January or February. Are such accommodations available?

ANSWER: Ixtapa, a resort area developed by the Mexican government in the 1970s, is adjacent to the old fishing village of Zihuatanejo, now also a resort.

Villa rental companies say that there are not as many villas or condominiumsin the area as in other Pacific resorts like Puerto Vallarta or Manzanilla.

The beachfront in Ixtapa, they say is dominated by hotels. Rental accommodations are generally about three-quarters of a mile inland, along the Palma Real golf course, which is to the east of the Ixtapa Sheraton. Here are some of the companies that have housekeeping properties in the area. Prices are for the winter.

Villa Holidays (13100 Wayzata Boulevard, Suite 150, Minneapolis, Min.. 55343; 800-328-626) represents two-bedroom, two-bathroom condominums on the golf-course. The condos, $207 a night with tax, share a swimming pool and tennis court. the company also has detached houses in the same area, some with private pools. Three-bedroom houses, the smallest available, start at about $375 a night.

Villas International (71 West 23rd Street, New York, N.Y. 10010; 800-221-2260 or 212-929-7585) also represents villas and apartments along the same golf course. They are rented by the week, with two-bedroom townhouse units atarting at $1,250. Rent a Vacation Everywhere (328 Main Street East, Suite 526, Rochester, N.Y. 146094; 716-454-6440) represents three-bedroom villas by the Palma Real golf course. The cost is $1,700 a week.

Four Star Living (640 Fifth Avenue, Fifth Floor, New York, N.Y. 10019; 212-603-4128) also represents two-bedroom villas and two-bedroom apartments by the golf course for $375 a night, which includes the tax, for a minimum of seven nights.