Political fallout from the nuclear accident in Chernobyl reached France today, with most of the press accusing the government of concealing information about radioactivity from the Ukraine.

The controversy, which produced such banner headlines as "The Radioactive Lie" in several Paris newspapers, followed two weeks of relative indifference here to the radiation leak. There is a general political consensus in France, the world's leading producer of nuclear energy after the United States, about the benefits of nuclear power.

By contrast with other West European governments, which issued regular communiques about the extent of radioactive fallout over their territory, French authorities limited themselves to reassuring statements about the lack of any significant threat to public health.

It was not until last weekend that figures were released by the Ministry of Health showing that radioactivity had risen to 400 times the normal level in parts of the country.

The decision not to publicize the figures earlier was made by the head of the ministry's Radiation Protection Service on the grounds that there was no need to alarm the population. The service now claims that radiation has dropped to normal levels after reaching a peak at the beginning of May, when radiation blew in from Italy.

Editorials in leading Paris newspapers today accused the government of treating the French public like children and behaving in a manner similar to that of the Soviet authorities by holding back important information. There was also criticism of the politically entrenched "nuclear lobby" of civil servants who oversee France's ambitious nuclear program, in addition to being responsible for safety and environmental protection.

In a front-page editorial headlined "Nuclear Disinformation," the Paris daily Le Monde said that the government's delay in publishing the figures constituted a "major psychological error . . . At a time when all the other Europeans were seeking to establish the truth about Chernobyl, the French silence resulted in the end in causing concern," the paper said.

Despite the sharp increase in radiation levels in the soil and in milk, French scientists maintain that the contamination posed no health hazard. By the most pessimistic scenario, a French citizen who drank 12.72 quarts of the most contaminated milk in the country for 12 days in succession would have digested less than one-tenth the annual safe limit of radiation.

Environment Minister Alain Carrignon today conceded that information about the radioactive fallout had been mishandled. He said the government would announce details of the formation of an interministerial committee to ensure that information is better distributed in the future.

Friday night, the Ministry of Agriculture announced a unilateral ban on foodstuffs from Eastern Europe, a move seen here as designed to forestall public concern about the government's inaction. The European Community today imposed a similar ban and agreed on common safety standards for all 12 Community countries.

In comparison with other West European countries, notably West Germany, the environmental movement is weak in France, which relies on nuclear power for 65 percent of its electricity. The country's civilian and military nuclear programs long have been regarded by both the media and the political establishment as virtually synonymous with French independence.

When the French secret services sabotaged a Greenpeace ship in New Zealand last year in order to halt a protest against French nuclear testing in the South Pacific, there was remarkably little public outcry here. Most French citizens took the view that the government was acting to protect French interests, even if the sinking itself was bungled and French agents arrested.

French environmental groups have complained that they have difficulty gaining a public forum because of the national mood of self-satisfaction, which until now has been reflected in the press.

"Nobody listens to us. It's not that we have no impact on public opinion, but we are gagged and constantly being accused of selling out to the K.G.B.," complained Rene Dumont, a leading French writer on ecological matters..

After accepting the government's silence for the past two weeks, the French press today appeared to be in a more self-critical mood, with Le Monde declaring that it had been "too gullible." The media here gave considerable attention to official reassurances that a weather front would keep the radioactivity from protruding into France from Italy and Switzerland.

First reports that radioactivity had reached France came not from the French government but from the tiny principality of Monaco on the Mediterranean coast.

The director of the Radiation Protection Service cited two holidays and the difficulty of compiling the data as reasons for the delay. Pressed by a television interviewer, he added: "In any case, my service is not a public relations agency."