PARIS (AP) _ Soviet leader Mikhail Gorbachev today left for Moscow after a four-day visit to France that made world headlines but failed to win European support for his new arms reduction proposal.

Gorbachev met with French Communist Party leader Georges Marchais a second time before leaving.

The Soviet leader and his wife, Raisa, were seen off by Premier Laurent Fabius at Orly Airport's VIP pavilion, where a boy and girl wearing Soviet Pioneer red scarves presented then with large bouquets. There were no formal speeches.

During the visit, which came seven weeks before his summit with President Reagan, Gorbachev proposed the Soviets conduct separate talks with France on nucler weapons reductions.

On Friday, President Francois Mitterrand dismissed the offer as well as Gorbachev's proposal for a joint communique condemning the U.S. space-based nuclear defense.

The Soviet and French leaders appeared at a news conference at the Elysee Palace where Mitterrand said his nation's nuclear ''force de frappe'' was too small to warrant negotiations.

Gorbachev responded by saying, ''We started going into this question only yesterday and it would be indeed strange for us to reach agreement today.''

The Soviet Communist Party leader has also proposed talks with Britain on its nuclear force, but London has reacted coolly.

Gorbachev, on his first trip to the West since assuming power in March, also announced a series of new proposals for the arms negotiations in Geneva, including a 50 percent reduction in U.S. and Soviet nuclear missiles ''capable of reaching each other's territory'' and a drop in the number of Soviet medium-range missiles.

The French say they have about 100 nuclear warheads compared to 7,000-8,000 each by the United States and the Soviet Union. Until now, the Soviet Union has insisted those weapons be included in the Geneva talks - a demand rejected by France and its Western allies.

Although Mitterrand refused to issue a formal joint communique on the space weapons issue, he agreed with Gorbachev that space weapons would make effective arms control impossible. Mitterrand's Socialist government has declined participation in President Reagan's Strategic Defense Initiative, commonly known as ''Star Wars.''

Gorbachev has repeatedly stressed his opposition to space weapons, and the issue is expected to dominate the Nov. 19-20 summit between him and Reagan.

The French president has turned down Reagan's invitation to seven major Western allies to confer in New York before the U.S. leader meets Gorbachev in Geneva.

French officials on Friday privately called Reagan's invitation ''something of a summons'' and said a rejection by Paris was needed so as not to appear in ''Washington's pocket'' during the Gorbachev visit.

Friday's news conference was the first for Gorbachev, who sometimes gesticulated for emphasis and occasionally smiled. The two leaders, who answered reporters' questions but did not talk with each other, wore headphones to listen to each other through interpreters.

France, which does not participate in the military wing of NATO, has 80 missiles on four submarines, 18 intermediate-range ground-based missiles and four squadrons of jet fighters equipped with nuclear weapons.

In Washington, President Reagan said of Mitterrand's rejection, ''That's his decision to make and I'll have no comment.''

Gorbachev said the Soviet Union has made many proposals for disarmament, the newest ones being offered ''to give impetus to the Geneva negotiations.''

He said he did not know if the Soviets would be able to continue to negotiate if the arms race were to extend to space.

Gorbachev said he believes Washington has made a serious response to the latest Soviet initiative in Geneva. ''It seems to me there is a maturing ... of thought,'' he said.

When the Soviet leader was asked about human rights his mood turned sour, he became vague, and at one point he abruptly dismissed a television reporter's question.

Mitterrand and the French prime minister, Laurent Fabius, have complained during the Gorbachev visit of Soviet attitudes toward human rights.

Mitterrand raised the subject in formal toasts and in his welcoming speech and Fabius presented Gorbachev with a list of seven specific human rights cases in the Soviet Union.