THE slow, difficult reemergence of Iran into the international community has been complicated by events in Lebanon and France last week.The official British "thank you" to the Iranian regime for its role in Thursday's release of hostage John McCarthy in Lebanon must have been music to the ears of Iranian leader Hashemi Rafsanjani, who continues to battle hard-line opponents at home over his efforts to open to the West. But at the same time, the assassination of former Iranian Prime Minister Shahpur Bakhtiar in Paris Tuesday, and the short-lived taking of a French hostage in Lebanon Thursday, have thrust France's accelerating relations with the Rafsanjani regime into a sudden downshift. Publicly, French Foreign Minister Roland Dumas says only that "at this stage it would be hasty to draw any conclusions" from the two latest events. "The French government thanks the governments of Lebanon and Syria for their vigorous effort in securing the release of our compatriot Jme Leyraud [on Sunday]," said a French Foreign Ministry spokesman yesterday. Privately, government officials say the warming relations, still in a tentative stage and complicated by unresolved financial issues dating from before the Iranian Islamic revolution in 1979, would be frozen by any proof of official Iranian involvement in either incident. For French officials and Iran observers alike, the taking of Mr. Leyraud as hostage has little connection to Iran. "We are not jumping to any conclusions, but we tend to agree with those who say the taking of hostages no longer holds any interest for any state," a source close to the Foreign Ministry said Friday. Leyraud's release after intense pressure from Syrian and Lebanese officials bears this out. The assassination of Mr. Bakhtiar and his aide in Bakhtiar's home outside Paris, however, is less easily separated from Iranian involvement. Bakhtiar, Iran's last prime minister under the shah, was said by other Iranian refugees to be among Iranians targeted for assassination by the Iranian authorities as recently as July. Some Iranian dissidents, including former president Abolhassan Bani-Sadr and Muhammad Reza Pahlavi, son of the last shah, immediately accused the Iranian government of the murders and said the West should end its warming to a criminal regime. Others say certain differences about this assassination leave them cautious about pointing fingers. Ahmad Salmatian, Iran's Secretary of State for Foreign Affairs under the first government after the revolution, is of this camp, although he says the political climate Iran's Islamic regime is still such that "normalization" of relations with the West and political assassinations are seen as complementary. According to Mr. Salmatian, who now operates a Paris bookstore, the Rafsanjani regime no longer faces serious opposition to its policy of opening up the Iranian economy to the West. "The economy is in a disastrous state," he says, "and the mullahs [religious leaders] now accept that the survival of their regime depends on Western involvement." What remains controversial, however, is the question of how opening to the West might influence the regime's "Islamic rigueur" and its "systematic repression of any opposition," says Salmatian. Given those worries, Salmatian says oppressive acts inside the country or actions such as assassinations outside are used to "balance" normalization with the West, and to "calm hard-liners" worried that the regime's leaders might be weakening their resolve against Western values. France's reaction to Bakhtiar's assassination is particularly important, says Salmatian. It will indicate whether the French and the West are prepared to normalize relations with Iran no matter what, or if Iran will be held accountable on such issues as human rights as a price to pay for Western economic involvement.