MINUTES after the lagoon at Mururoa Atoll foamed white from the impact of France's first underground nuclear test in four years, Paris felt the blast of world protest. But French officials insist they will not blink. ''Nothing has changed,'' French Foreign Minister Herve de Charette said at a press conference yesterday. ''We weren't surprised by the number or by the nature of the world reaction.'' France would continue its program of up to seven more nuclear tests as planned, he said. Condemnation of France's new test in the South Pacific Tuesday was intense. New Zealand and Chile recalled their ambassadors from Paris, and Japan registered an official protest. The South Pacific island of Nauru pledged to break diplomatic ties with France; others island nations are expected to follow. Australian Prime Minister Paul Keating said the tests expressed French ''contempt for the countries and people of the region.'' European Commission President Jacques Santer yesterday refused to condemn the French tests, but individual European Union states stepped up pressure. Germany and the United States avoided direct condemnation of France but renewed calls for an end any further nuclear testing. Meanwhile, the environmental group Greenpeace rallied protesters to dress in mourning for a demonstration in Paris yesterday. In Austria, protesters stormed the French embassy. FRENCH officials say they can win the battle for public opinion in the long run, at least at home. While 63 percent of French citizens in the latest opinion poll oppose nuclear testing, two-thirds still favor maintaining a nuclear deterrent. Much of the criticism of the French program has focused on the dangers of contamination. The release of a new series of tests by the Vienna-based International Atomic Energy Agency last week confirmed French claims that testing to date has not resulted in abnormal levels of contamination. Some antinuclear activists now say that the focus on contamination may have been a mistake. ''Contamination is not the real issue, it's disarmament,'' says Ben Cohen, who quietly resigned from Greenpeace France in July after directing that organization's research on disarmament for the last three years. ''Greenpeace is focused too much on television visuals and Hollywood-style publicity. They're missing the key issue: the ambiguous frontiers between proliferation and nonproliferation. ''At least we know what France is doing with its nuclear test program. They've been transparent,'' he adds. Once nations convert to computer-simulated testing, as France plans to do, ''We'll have much less control of what official proliferators are doing.'' While some critics insist that the end of the cold war eliminates the need for nuclear weapons, France has longer-term reasons for wanting to maintain its arsenal. French officials are convinced that a nonnuclear world is not possible. ''France has always refused to identify an enemy for its nuclear deterrent,'' says Frederic Bozo of the Paris-based French Institute of International Relations. ''Now, after the cold war is ended, that is even more the case. Unlike Germany or Japan, France has never accepted the view that nuclear weapons will disappear from the earth. As long as they don't, a deterrent will be needed.''