French banker Guy de Rothschild yesterday called on America to help - but not intervene in - his country's efforts to get out of current economic and political problems.

Speaking at a luncheon at the International Club for visiting French business leaders, the chairman of the board of the Banque Rothschild said it would be a pity if this country disregarded the current swing toward socialism in Europe. 'If it took a turn for the worse, you would wake up and feel very sorry,' he remarked.

The baron, who is one of the richest men in France, spoke candidly of the "risk of upheaval, the paralyzing effect detrimental to our economy" that might follow a socialist victory in next March's general elections.

At the same time he sought to reassure American businessmen (with money to invest in France) that French businessmen are not a reactionary group, but "open to evolution, social minded and willing to go along with the new ways." French socialists are more utopian than socialists of Northern Europe like Olav former Swedish prime minister Olav Palme whose "boredom" caused his people to turn him out of office, Rothschild said.

In fact, 10 months before the elections, which Socialist leader Francois Mitterand is expected to win, the French stock market is already reacting negatively. Capital investment is way down and capital flight has become a major problem in France.

Rothschild argued against protectionist tarriffs and for a liberal expansionist policy. "We fear that a too super orthodox policy regardidng inflation might be very good here, but would go counter to what we would like in Europe. Let a little of your expansion overflow with us," he said.

He called it "not helpful and slightly unfair" that the United States was trying to curb the products of France's technological advance that earn it foreign currency. He specifically cited breeder reactors and the Concorde jet. Why is it, he asked, that the "noise of a 747 is music, while the noise of a Concorde is ear-splitting?"

Prime Minister Raymond Barre's newly appointed minister of foreign trade, Andre Rossi, also is visiting Washington in anticipation of the London economic summit. In remarks yesterday to the same meeting, Rossi cited several American practices he considers obstacles to increased trade: eight different possible system of customs duty evaluation so an exporter doesn't know the price before shipping; conflicting state and federal laws, and what he said was a failure of the U.S. to apply international rules on countervailing duties and antidumping measures.

Rossi also singled out what he termed very high duties levied on certain French exports: textiles, cognac, and specialty steel products. He pointed out that textiles are liable to duties in excess of 50 per cent and up to 100 per cent whereas European duties are about 30 per cent. "So a uniform reduction would mean that only the American tariffs would remain serious deterrent to trade. This, of course is not acceptable," he said.