It didn't take long. Claude Cheysson, the new French foreign minister of the Mitterand government, had been in town but two days and already was under the president's spell.

"He is a man of such personality, such unexpected personality," said Cheysson at the elegant reception at the French Embassy last night in honor of both Secretary of State Alexander Haig and himself. "I was quite under his charm. And I must say, it was a very nice gesture for him to stay and see me this afternoon before leaving for Camp David."

Nice gestures, of course, are what official visits are all about. This one was also a chance for the French foreign minister to explain the policies of his socialist government to the Reagan crowd. "Some of the misunderstandings have been cleared up," said Cheysson of meetings at the White House, and with the secretaries of Commerce, Treasury and State. "We are no fools," he explained, "we want to be a success."

The dinner came just hours after Ernest Lefever, the Reagan administration's embattled nominee for assistant secretary of state for human rights, withdrew his name from consideration. That withdrawal came after the Senate Foreign Relations Committee rejected his nomination 13 to 4. And so the affair was prime cocktail chatter.

Nearly all of the guests expressed surprise at Lefever's decision, but not all of them were sorry to see him go.

"I think you could say we were surprised," said presidential counselor Edwin Messe. And would the post be filled? "We haven't made any decision about that."

"I regret it," said Haig of the Lefever decision. And as for the job itself, "We had strong reservations about the post from the beginning, in terms of its role. It's something to be discussed."

"I wouldn't rule it out," said Senate Foreign Relations Committee chairman Charles Percy (R-Ill.) of leaving the post unfilled. "I'm not sure the job is essential if you're trying to scale down government. I'm wondering whether the timing is right. I'd rather have had one in the post than Ernest Lefever."

National Security Adviser Richard Allen walked in, quickly ordered a Perrier, and greeted Cheysson briefly. He too had something to say about Lefever.

"He's a friend," said Allen. "I talked to him afterward."

"It was a wise thing to do," said Foriegn Relations Committee member Sen. Charles Mathias (R-Md.), of the withdrawal.

The guests, including protocol chief Leonore Annenberg, Secretary of Commerce Malcolm Baldrige, World Bank president Robert McNamara and Sen. Russell Long (D-La.), gathered first in a yellow hung with large oil paintings before sitting down to a dinner of filet of sole, Canton duck and glace Rothschild.

"Ah, three industrialists here," said Percy, standing with McNamara and Baldrige.

"At least one is ex," said McNamara.

"We'll we'd better not stand too close together or they'll accuse us of price-fixing," Percy replied.

Leaning up against the fireplace decorated with bronze gods on gold pedestals, were Walter Annenberg, U.S. ambassador-designate to West Germany, Arthur Burns and Mathias. "You're a rascal," said Burns to Mathias. Mathias, sporting a deep tan he said he'd acquired in his cornfields, had to agree.