Louis XIV built it and the rest of his life had a running love affair with the palace of Versailles. Charles de Gaulle had other feelings. He once described it with a line that became a classic: "One hundred thousand houseguests couldn't make it a home."

That may be the only thing French President Francois Mitterrand and his old adversary de Gaulle ever agreed upon. Instead of Versailles, Mitterrand is putting up President Reagan and six other VIP houseguests at the June 4-6 economic summit nearby in Le Petit Trianon, Marie Antoinette's little hideaway until she ran out of cake.

"It's not normally a place to stay," says one French government official of the 18th-century chateau that Louis XV built for his trysts with Madame du Barry. Louis XVI later gave it to Marie Antoinette, and she kept a herd of very picturesque cows in the side yard so she and her ladies-in-waiting could play at being milkmaids. She fled to the grotto on the chateau's grounds in October 1789, when Paris mobs marched on Versailles.

All that past is certainly not prologue but just a little historical perspective for what Francois Mitterrand has ordered done to the place. The French are busy installing modern bathrooms at Le Petit Trianon.

President Reagan and the leaders of Germany, Canada, Great Britain, Japan, Italy and the European Economic Community will shuttle the two kilometers to Versailles Palace for what's scheduled to be 30 hours of talks in the Salle du Sacre. That's the room where David's painting shows Napoleon crowning himself emperor while the Pope looks on with nothing to do.

Wives (and presumably Margaret Thatcher's husband) won't be included at two of Mitterrand's three dinners ("It's a very serious meeting," explains the French official.) Neither are they staying at Le Petit Trianon. But spouses shouldn't feel neglected; Mitterrand's third dinner, to which he's inviting 200 guests, will be in the Hall of Mirrors. You can't do much better these days.

Meanwhile, an estimated 3,000 reporters are clamoring for summit press credentials. White House telephones ring daily with interview requests to Nancy Reagan from Europe's mass media. She's already done a couple that will be published in France and Italy before she arrives. Others, says her press secretary Sheila Tate, are out of luck.