France's trade minister, Edith Cresson, yesterday defended its agriculture subsidies and said her country would resist any pressures by the Reagan administration to cut its farm exports.

Cresson spoke at a press conference that marked the end of a U.S. visit in which she promoted sales of French household goods at a show in Chicago and sponsored a seminar here for French businessmen who want to invest in U.S. companies.

Her press conference, however, was dominated by questions about France's staunch opposition at the Bonn economic summit to a U.S. request to set a 1986 date for new global trade talks.

That opposition is seen by the Reagan administration as a French move to stall attempts to end European agricultural subsidies. In the administration view, these subsidies give French and other European farmers an unfair advantage over American products in third-country markets.

But Cresson and her aides insisted that the French view is misunderstood in this country and that Paris is sticking to the common position of the European Economic Community, from which Britain and Germany deviated. All France wants, she said, is "strict preparation" of the agenda for a global round and an assurance that the interests of less developed countries are represented.

She also denied that Europe's subsidized farm exports are hurting American farmers, whose own overseas sales are expected to drop in 1985 for the fourth straight year.

"Other countries have moved in because of the high dollar and embargoes, which are the real causes of the loss of U.S. markets," Cresson said. She named Argentina, Australia and Canada as countries that took advantage of U.S. embargoes to move into markets that previously had been held by Americans.

She pointed out that European exports have held a steady 15 percent of the world grain market over the past four or five years. In the same period, she said, the U.S. share decreased from 42 percent to 38 percent. But Argentina more than doubled its exports, from 4 million tons to 9 million tons, as a result of the U.S. grain embargo on Soviet sales, she said.

Meanwhile, at the White House, key lawmakers, after receiving a briefing from President Reagan on the Bonn summit, said France's refusal to go along with a starting date for a new round of global trade talks is increasing protectionist pressures here.

"If the French proceed to drag their feet on trade talks, it will come sooner than later," Senate Majority Leader Robert J. Dole (R-Kan.) said after leaving the White House. He said he expressed that opinion to the president.

Rep. Dan Rostenkowski (D-Ill.), chairman of the House Ways and Means Committee, said the discussions with President Reagan were dominated by trade and focused on "the unfairness of the closed markets in the rest of the world."

Sen. Alan Simpson (R-Wyo.) said the congressional leaders told Reagan that Congress will pass protectionist legislation if markets don't open, even though "we would just hurt ourselves if we went that way."

For her part, Cresson said that a trade war would hurt both the United States and Europe. "I don't know if that is wished here," she added.

She said her government is helping French companies to invest in the United States to shield them from possible U.S. protectionist actions by making them part of the American economy.

"We fear the rise of protectionism," she said, and the best way to neutralize it "is to play the game with the Americans. This means to participate."