FRANKFURT AN DER ODER, GERMANY — ON weekends, Germans stream over the bridge here at Frankfurt an der Oder. Their destination lies about a mile into Poland, on the other side of the Oder River, in a little hollow surrounded by tall trees.This is the site of the Polish bazaar in Stubice, where Germans flock to booths to buy sausages, cheese, vegetables, and fruit at bargain-basement prices. In heavily accented German, the Polish vendors bellow out prices for other wares as well: blue jeans, shoes, Polish crystal, and cassette tapes. The scene is repeated up and down the Polish-German border, where towns from both countries sit directly across from each other and where a border crossing connects them. It illustrates how - on a small scale - the Germans and Poles can benefit economically from each other. German and Polish political leaders, however, would like to see this kind of economic integration on a much bigger scale, and they specified development of the border region in the historic friendship treaty signed between Bonn and Warsaw last June. Plans for an economic zone, which would extend 100 kilometers (62.5 miles) into Poland and 50 kilometers (31 miles) into Germany, are still under discussion. They include the creation of a German-Polish development bank; a duty-free port at Szczecin (formerly Stettin), which used to serve Berlin; and the fostering of appropriate industry for the area, such as food processing centers and lumber mills. Sharing rivers, ground water, and air, the Germans and Poles have common environmental problems, and officials from both countries would like to clean up the pollution and establish a single large nature reserve in the north. Both countries hope these steps will also spur growth in tourism. While the political will is there (at least among the elite), actual integration may prove difficult to accomplish - not only because of language, but also because of economics and history. The atrocities of World War II have left the Poles with little love for the Germans. But feelings expressed by many Germans, especially the millions expelled from Poland at the end of the war, are also bitter. After the war, the relationship never fully recovered. Poles and East Germans were supposed to be comrades in communism. But when Solidarity blossomed in the shipyards of Gdansk, the East Germans put their neighbors at arm's length, restricting travel between the countries. "Before the big changes, cooperation between Poland and East Germany was more or less ideological cooperation," says Wiktor Jasiewicz, deputy mayor in Stubice, a shabby town which sits across the river from Frankfurt an der Oder. Both towns now have big plans. They want to build a joint sewage treatment plant, coordinate waste removal, link local transportation, and open a European university. "What we want now is real cooperation ... but we have absolutely no experience in this," says Mr. Jasiewicz. Even though communist governments embraced, relations on the personal level were chilly. Erika Kruse can attest to that. Mrs. Kruse is selling honey at a roadside stand in the German town of Kietz, which is being considered as a site for a new border crossing. She recalls how angry she would become when Poles shopped in East German stores under the old regime. "They used to milk us dry! They would walk away with whole wursts, while we waited in line for a piece," Kruse says. She describes working in Poland for two years: "Children would shoot us with sticks, calling us Hitler fascists." A border crossing at Kietz? No, thank you. But not all Germans and Poles share these sentiments. An elderly Polish woman, keeper of the keys to a peeling church in Kostrzyn, across the river from Kietz, is baffled by the suggestion that regional cooperation would lead to German dominance. "That's just politics," she says. A German farmer loading cauliflower onto a truck in Kietz, calls Poles "good workers." This year, as in years before, Poles swarmed the area, helping with the harvest, he says. "They do jobs Germans won't do. They're cheap. They work hard." Whether Poles are good workers or not may be a moot question if the economic development of the region goes forward as suggested. A study commissioned by the finance ministries of Berlin and the state of Brandenburg, which shares a long border with Poland, suggests that agriculture be greatly reduced in the region. An official from Brandenburg says that farming has become an environmental hazard. On both sides of the Oder and Neisse Rivers, the soil is sandy and requires an enormous amount of chemicals and fertilizer, which pollute the ground water. Besides, he says, Europe is already overloaded with food surpluses. Instead, the study proposes fostering tourism, small and medium-sized businesses, the service industry, trade, and office parks for high-tech industry. But such plans require an infusion of Western capital and a near total reorganization of the region's economy. Farming, for instance, is a key means of livelihood on both sides of the border. And the German towns which run along the border are not smorgasbords of medium-sized businesses; they are all one-industry towns. While the region is picture-book pretty, with lakes, a seacoast, and rolling hills, it lacks the guest houses and hotels to accommodate tourists. Nearly everyone here is optimistic about the region as a trade crossroads, not just between East and West Europe, but between north and south as well. In Frankfurt an der Oder, the main transit checkpoint, the potential is evident in the lines of trucks waiting to cross the border. But the lines also hint at the hurdles to trade. With German reunification, the border of the European Community (EC) has shifted east and abuts Poland. For months, the German press has reported only one implication of this change: the thousands of East Europeans camping on the edge of Poland and the daily battle to keep them from slipping into Germany. Another implication is the effect on trade. Lengthy customs procedures won't fall away while Poland remains outside the EC. To relieve congestion, Warsaw and Bonn may add at least five border crossings and recommission ferries. Detlef Ewert, deputy mayor of Frankfurt an der Oder, says national and state politicians would be wrong to believe they can promote growth and cooperation in the border strip by ordaining it from above. "For years, friendship between Poland and Germany, that is, East Germany, was on the government level. We don't think this works," Mr. Ewert says. "Here in Frankfurt and Stubice, we think it should grow from the bottom up, from the communities outward." This has worked with France, he says. It can work with Poland, too.