PARIS (AP) _ Freed hostages Camille Sontag and Marcel Coudari stepped off a French government plane last Tuesday, were embraced by Premier Jacques Chirac, were quizzed rapidly by reporters, and walked away into near obscurity.

Aside from the new hearing aid the 85-year-old Sontag was given by his wife, the French people have learned little about the former hostages' health, their adjustment to freedom or their views on what should be done about the six Frenchmen still missing in Lebanon.

In the first days after American David Jacobsen was freed Nov. 2, ending 17 months of captivity in Lebanon, his every step was closely followed - from his medical examinations in West Germany to his meeting with President Reagan in the Oval Office.

On Friday, Jacobsen told a news conference in California he would fly to London to work toward freeing other hostages and would be willing to return to Lebanon, where six Americans are still missing.

Neither Sontag nor Coudari has been seen in public since Tuesday night. That morning they appeared at the Syrian Foreign Ministry in Damascus, were greeted by French officials and put on a special plane to Paris.

Sontag hugged his wife, was welcomed by Chirac, posed for photographers and was gone within minutes. Mrs. Sontag said she fixed lamb chops for dinner.

Coudari, 54, faced more aggressive questioning, in part because of mysteries in his past. But he refused to answer and left within an hour for a nephew's home outside Paris.

French news coverage of the hostages has been dominated by analyses of what France may have done to win freedom for Sontag and Coudari, and what price Iran, Syria or the hostage-keepers might demand before others are let go.

There seems to have been little curiosity about the ex-hostages' return to society.

''It's partly the national character. People say, 'Leave them to their families, leave them alone, after what they've suffered,''' said Dominique Moisi, associate director of the French Institute for International Relations. ''There's an element of culture involved.''

Even more important, perhaps, is that Coudari and Sontag were the least known of the French hostages, said Jean-Francois Held, editorial director of the news magazine L'Evenement du Jeudi, whose reporter Jean-Paul Kauffmann is among those still held.

Held said, ''If Kauffmann comes out tomorrow, I think it will be talked about a lot.''

Sontag, a retired automobile dealer, lived 40 years in Beirut. He was planning to return to France when he was abducted on May 7 by the Revolutionary Justice Organization, which is believed made up of pro-Iranian Shiite Moslems.

Coudari was kidnapped in February, but his disappearance was not reported until September when the Revolutionary Justice Organization said it was holding him. Although born in France, Coudari lived much of his life in the Middle East and became a French citizen only in 1982.

Reporters didn't ask Coudari how it felt to be free, but whether he would comment on published reports that he had a criminal record in Switzerland, was involved in drug traffic, or was a secret agent in Lebanon. He declined comment.

While Sontag has not been heard from since the day he was freed, Coudari surfaced last Friday to deny a news report that before he was abducted he was an ''emissary'' of a French security force trying to win freedom for hostages in Lebanon.

''If I were a spy as people say, they would never have got me out,'' Coudari said in an interview on French radio.

He asked the news media to respect the suffering he has undergone and ''leave me in peace.''

Later Friday, in a statement delivered to the French news service Agence France-Presse, Coudari said vaguely that for many years he served ''notably in the Middle East the interests of France as any Frenchman would have done, using all his capacities.'' He said commentaries were not appropriate while ''other hostages, whose fate is still uncertain, are imprisoned in Lebanon.''

Coudari said he ''has therefore decided to leave to the conscience of the press the need to halt all polemic'' and ''to remain from this day totally silent on this affair.''