The French government today forced the leader of a left-wing Iranian opposition group to leave the country in a move interpreted here as a conciliatory gesture toward Tehran and the pro-Iranian kidnapers of French citizens in Beirut.

Massoud Rajavi, leader of the Mujaheddin-e-Khalq which has been waging a guerrilla campaign against the Iranian government, flew out of Paris this afternoon aboard a private aircraft. He had been in exile here since July 1981.

The departure of Rajavi, which was combined with a police crackdown on his followers in France, has removed a major obstacle to an improvement in relations between Paris and Tehran and could be part of the price for the possible release of French hostages in Lebanon.

Today's developments come against a background of complex negotiations, involving both Iran and Syria, for the release of nine Frenchmen kidnaped in Beirut over the past year.

Rajavi later received a red-carpet welcome in Baghdad, Reuter reported, citing the Iraqi news agency. The agency said he was greeted by First Deputy Prime Minister Taha Yassin Ramadan and Defense Minister Adnan Khairullah.

Although French police said that no expulsion order had been served on Rajavi, it was clear that his sudden departure was the result of intense government pressure.

Prime Minister Jacques Chirac said last month that the government would crack down on what he called the "excesses" of Iranian political exiles in France.

Rajavi's sudden departure followed a large-scale police operation at Auvers-sur-Oise, a sleepy village near Paris best known as the home of the painter Vincent van Gogh until it became the headquarters for the Mujaheddin. Police checked the identities of about 60 Mujaheddin supporters, including bodyguards and secretaries, at Rajavi's bunker-like residence.

In a series of interviews during the past five years, Rajavi openly stated that his aim was to overthrow the government of Ayatollah Ruhollah Khomeini.

In addition to raising money for guerrilla groups operating inside Iran, the Mujaheddin issued a constant stream of press statements denouncing alleged human rights abuses committed by Tehran.

Together with Iraq, France has long been a favored place of exile for Iranian opposition politicians. Khomeini lived here for three months before his triumphant return to Iran in February 1979 at the height of the Islamic revolution.

Political analysts said the presence of the anti-Khomeini exiles had become embarrassing to the French government at a time when it is seeking to negotiate an end to the hostage crisis in Beirut.

The kidnapers have repeatedly called for French concessions to Tehran and an end to French support for Iraq in the Persian Gulf war as conditions for the release of the hostages.

French officials said that progress has been made on an Iranian demand for the repayment of $1.5 billion in assets that were frozen by France after the Iranian revolution.

But France continues to be the major western arms supplier to Iraq, and there seems little prospect that Paris would agree to ending such a lucrative and politically important relationship.

Today's police action still leaves several other leading Iranian exiles in France, including the shah's last prime minister, Shahpour Bakhtiar, and former president Abol Hassan Bani-Sadr.

Once close allies who escaped from Iran together, Rajavi and Bani-Sadr quarreled in April 1984 after the Mujaheddin leader signed agreements with Iraq.

Criticizing his former ally, Bani-Sadr today said that Rajavi was paying the price for his political dependence on "foreigners." Both he and Bakhtiar said that they had received no indication that they also would be asked to leave France.

Informed French sources said Rajavi was accompanied on his flight out of France by five other people including his wife. They added that several dozen Mujaheddin supporters have left France over the past few weeks as the result of police pressure.

The French crackdown against the Mujaheddin followed a visit here last month by Iranian Deputy Prime Minister Ali Reza Moayeri, marking a resumption of high-level ties between the two countries after a six-year interval. The Iraqi deputy prime minister, Tariq Aziz, is due in Paris next week.

French officials have recently expressed optimism about a possible breakthrough in the hostage crisis following secret contacts between the kidnapers and the Syrian and Iranian governments.

In a radio interview last week, Syrian Defense Minister Gen. Mustafa Tlas said that the release of the French citizens seized in Beirut was just "a matter of time."