RODERICK MANN : OUT OF THE TREES--AND UNDERGROUND

Christopher Lambert first came to our attention when he swung down from the trees of West Africa to wind up as lord of an English manor in the movie “Greystoke: The Legend of Tarzan. . . . “

But where do you go from there? Friends soon tire of ape impersonations. And Lambert, who lives simply, was determined not to fall into the same trap as earlier Tarzans like Johnny Weissmuller and Lex Barker, who never escaped the image.

So he said a firm no to offers intended to capitalize on his tree-climbing ability (surprisingly, there were several) and went home to France. Although born in New York, his parents are French and he regards Paris as home now. There he looked around for something different.

And in “Subway,” opening Friday, he hopes he found it. The greater part of the movie takes place in the Paris Metro where he, playing a spiky head character named Fred, takes shelter after blowing up someone’s safe and stealing papers. Co-starring in this film by Luc Besson (“Le Dernier Combat”) is Isabelle Adjani.

“We spent 15 weeks shooting underground in the Metro,” said Lambert, in town the other day and looking very different from his “Tarzan” days--in part because he is unshaven for possible retakes on a new movie. “It wasn’t easy, but it was an interesting film to make. The average age of the unit was 26--Luc Besson’s age. It would have been even lower if we hadn’t used Alexandre Trauner as our art director. He’s 82.”

Lambert insists that “this isn’t just another little French movie. I think Americans will like it. And subways look the same all over the world, so it has international appeal.”

He wants to make international movies if he can.

“If I stay in France, I know the sort of films I’ll be offered for the next five years,” he said. “Which is boring . Also, French movie making is so casual compared to the British and American way. A few French actors are less than professional, I’m afraid.

“When I was making my recent film ‘Highlander’ in London, Luc Besson came on our set and was absolutely amazed how organized and efficient everything was compared to France. There everyone takes it easy and expects you to do the same.”

In “Highlander,” in which he stars with Sean Connery, Lambert plays a Scot, circa 1500, complete with kilt. And although it was not much discussed, he was all too aware of the battle Connery has had to fight to try to rid himself of the James Bond image.

“So although there’s now talk of a ‘Greystoke II,’ I won’t do it,” Lambert said firmly. “I’ll read it if it’s sent to me, but I won’t do it. For me, that story is over. It would be a disaster for me to play the role again. . . . “

EXPENSIVE: London’s busiest theatrical producer, Duncan Weldon--he has four productions scheduled there during the next few weeks--came here to attend the Los Angeles openings of two of his London hits: “Old Times,” with Harold Pinter, and “Aren’t We All?” with Rex Harrison and Claudette Colbert.

The difference in the cost of staging productions here still alarms him, he said.

“In London last year our break-even point for ‘Aren’t We All?’ was 23,000 a week (at the time, around $30,000),” he said. “Here they tell me it’s $238,000. I find that absolutely incredible.”

BACK TO WORK: Twelve-year-old Edoardo Ponti, now at school in Geneva, will appear with his mother, Sophia Loren, when she makes her return to the big screen in Hall Bartlett’s “Leaving Home,” which starts shooting Jan. 13 in Stockholm.

In the film Edoardo will play Sophia’s son. He wants to be an actor. With his older brother Carlo, 16, he attended acting classes this summer at the Lee Strasberg Institute here when the family was in residence at their Hidden Hills home.

Bartlett is delighted to have them both. “It’s an Earth Mother role for Sophia,” he says, “the kind she played in ‘Two Women.’ ” He’s also delighted that Ingmar Bergman, whom he visited in Sweden earlier this year, has promised him the use of his facilities and some of his crew for the movie.

“And that is exciting,” said Bartlett.

GALA NIGHT: The entire cast of Broadway’s “A Chorus Line” has been invited to the Dec. 9 benefit premiere of Richard Attenborough’s movie version of the show at Radio City Music Hall.

Afterward, there’s a dinner-dance at the Waldorf. Among those expected to attend--let’s hope--are Fred Astaire and Ginger Rogers.