Once wiped out by looters during the riots of 1968, four times a victim of robberies at gunpoint, master tailor Georges de Paris Christopoulos faces another personal crisis today - the prospect of eviction from his two-room shop on the second story of a turn-of-the-century building in an old part of downtown Washington.

"I'm not going," says Christopoulos, who opened his business in 1967 at 618 12th Street NW.

He is one of a number of small businessmen-two hat shops, one discount house, one florist, one military clothier, one embroidery company, one doctor, and one museum-who face the constant threat of eviction as part of a city government plan to turn the area over to a private developer.

The city's housing agency, which owns eight turn of the century brick buildings fanning out from the corner of 12th and G streets, issued eviction notices to the businessmen and one resident after eight years of off-again, on-again development plans.

The Landow Company of Bethesda has won the exclusive right to propose a development plan for the site. The company wants to construct a 10-story concrete and glass office and retail building on this and an adjoining site.

The Redevelopment Land Agency, which became part of the Department of Housing and Community Development in 1975, purchased this and other sections of downtown Washington to encourage redevelopment.

The 12th and G streets corner and other whole blocks of old downtown are being redeveloped as Washington's real estate boom catches up with the city's oldest retail area.

The notices to quit the buildings came 1st November. That 90-day notice was followed by an extension to allow the merchants to stay open through Easter. The final 30-day notice was to have expired today, but a last-minute reprieve came through.

Late yesterday afternoon, Jim Wollfork, who is in charge of relocation of commercial properties for the city's housing agency, said the agency would rescind or alter the notices sent to the businesses of the 12th and G Streets NW development site.

"We decided today to take another look at our construction schedule to allow the merchants to stay in business as long as possible. This in no way delays the development of that site," he said.

He said that letters will go out today to notify the tenants they have been given more time. Wollfork said he does not know how long the extension will be. "It might be one day, it might be a week" he said.

When Christopoulos was told he has more time in his shop, he said, "Those people make a lot of noise to upset people. I wasn't leaving anyway.

"I took in today a suit to alter. I wouldn't do that if I were leaving. I say we will be here through July and August. They are going to tear down building but it never has happened."

Jimmy Muscatello has run his military and civillan clothing store at 614 12th Street NW for 20 years. He has relocation rights. That is, the city is obligated to help him find new space.

Muscatello founded a group, Businessmen Affected Severly By Yearly Action Plan, to try to prevent the city from buying downtown properties for urban renewal. In 1970 there were 129 members. Now there are about 29, according to Muscatello.

"The little businesses lose to the big guys," he said. "The big guy comes along and buys up all the little buildings and tears them all down and puts up a big building that none of us can afford."

Neither Harry Shapiro of Maison's Hat Store nor Dan Gampel of the ABC Lettering & Embroidery Company had planned to vacate their stores today, even before the reprieve came through.

Shapiro, unlike the other merchants, says he is anxious to return to the same site. "I have confidence in G Street; i want to stay on G Street. I'd like to return to a big, new building," he said.

The Museum of Temporary Art, at 1206 G Street NW, had also received a notice to leave. Ironically, the museum owes its very existence to the city's housing agency. In 1974, under an innovative program to allow nonprofit groups to occupy empty city buildings, RLA rented the four-story building to the museum for the cost of the utilities.

"We made a deal with the city," said Janet Schmuchal, the museum's coordinating director. "They would give us the building and we would run a people-oriented business. We made art things happen," she said.

In five years, Schmuchal said, the museum has shown 476 artists in 32 shows and has held 11 performances with 72 participants. Their latest show, titled Nuclear Meltdown, closed May 12.

Schmuchal appealed yesterday to Mildred Bautista, the mayor's adviser on cultural affairs, to stop the eviction. The appeal succeeded, and the museum may be able to relocate in another RLA building across the street.

Morris Chabbott, owner of House hold Discount Stores at 1208 G Street NW, is leaving. The front windows of his store are covered with large signs saying that the store is being forced out by RLA.

"We've had a month-to-month lease with RLA for seven years," Chabbott said. "We'd fight it if we thought wecould win. But you know, it's like a first love, or a first marriage - you remember the happy times and you go on," he said.

Joyce A. Cappon, the city's project coordinator for the 12th and G street corner, is sympathetic to the longterm businesses there.

"It's a microcosm of what is happening in whole city," she said. "Downtown is exploding and here is this little corner sucked into that explosion."

Nathan Landow, the developer for the property, could not be reached for comment. His partner, J. Gerald Lustine, said the new building will encourage an assortment of boutiques on the ground floor. "Downtown should offer everything that Tysons Corner offers," he said. Groundbreaking for the newbuilding is scheduled for November. CAPTION: Picture 1, Small business located at 12th and G streets are to be evicted so that a large office and retail building can be constructed there, Photos by Linda Wheeler-The Washington Post; Picture 2, Georges de Paris Christopoulos, a tailor located at 618 12th St. NW, plans to flight his eviction, By Lindawheeler-The Washington Post