A genuine "first" occurs Wednesday when an international wine and cheese festival opens at the D.C. Armory. Sponsored by the Maitres des Tastevin, a Rockville organization, the ambitious six-day festival promises something for wine lover and novice alike.

According to F. Ronald Hines, president of the sponsoring organization, the Armory will resemble a multi-ringed circus. While panels of wine experts evaluate several hundred American wines, the public will be entertained in an international setting reflecting the style, wines and cheese of France, Germany, Spain, Portugal and Italy as well as the United States.

There will be half a dozen daily seminars and an equal number of food demonstrations. Chef Jean Troisgros of the three-star Troisgros restaurant in Roanne, France, heads the list of culinary guests. He is scheduled to demonstrate at 8 p.m. on Wednesday. Visiting wine dignitaries include Burgess Meredith, wine writers Alexis Bespaloff, creighton Churchill, William Clifford, Robert Lawrence Balzer, Henry Rubin, Robert Misch and Norman Roby. Their work as tasters probably will be visible through one-way glass, Hines said.

The public is expected to sample a broad range of wines. Some will be served as free samples; others will be for sale in splits or carafes. The same holds true for cheeses from the countries listed above. Ethnic meals prepared by instructors and students from the Culinary Institute of America also will be sold.

In addition to the seminars and demonstration, there will be hourly film showings. Educational material will be available at booths. Live music will be played each day to simulate a fair atmosphere. Hines said he anticipates an attendance of 75,000 or better for the event, the first of seven Maitres des Tastevin hopes to sponsor in various cities.

Festivities take place from 4 to 10 p.m., Wednesday through Friday and Sunday; 1 to 10 p.m., Saturday, Oct. 22, and 1 to 9 p.m., Monday, Oct. 24, the Veterans Day holiday. Parking will be available in RFK Stadium lots.

Tickets for the festival will be sold at the Armory each day. They are priced at $6 for adults, $4.50 for persons under 18 (accompanied by an adult) and $3 for senior citizens. For information on reduced price advance tickets and group rates, call the Matires des Tastevin office, 770-WINE.