OLDER WRITER, YOUNGER MAN IN 'CET AMOUR-LA'.

Byline: - Bob Strauss

SOMETIMES a great actor in a perfect role can be all that a movie needs. In the case of ``Cet Amour-La,'' it's all that the movie has got.

But it is enough. French grande dame Jeanne Moreau could not be more magisterially right to play literary lioness Marguerite Duras, the Vietnam-born author (and sometimes filmmaker) of such works as ``Hiroshima, Mon Amour,'' ``India Song'' and ``The Lover.''

With her famously fallen face and a voice that sounds scraped with splinters from the finest French oak wine casks, Moreau fully embodies the semi-reclusive, alcoholism-wrestling writer in her final years, essentially from 1980-96.

But more than just these physical aspects, Moreau brings to the role the sophistication, creative passion and weary wariness only a fellow great artist could evoke with such effortless conviction. That both women possessed wicked humor - and, presumably, as much insight into themselves as their work proves they had for others - simply makes for as complete a filmed portrait as any biopic has ever attempted.

Trouble is, this thing is supposed to be a two-hander, and only one of them is clapping. Directed in a hermetic manner by Josee Dayan, who comes from a French colonial background herself, the film is based on the book by Yann Andrea. Following an appearance at Andrea's university in 1975, Duras so infatuates the philosophy student that he writes to her up to five times a day for five years. When the letters stop, she invites him to finally come visit at the Normandy beach resort where she summered. Though Duras is 38 years his senior, Andrea becomes her lover for the rest of her life - not to mention muse, typist and frustratingly unmotivated object of her mentoring instincts.

Played by the pouty Aymeric Demarigny, Andrea is a particularly blank slate. Yes, he occasionally bolts from and whinnies at his kept-man status, but Andrea's devotion to Duras is never really questioned. Nor, unfortunately, is it examined very well; we're told that he likes her writing and get hints that without some difficult, demanding and unusual person to devote his life to, he'd probably just take it by his own hand. But that's about it.

While this could well be quite factual, it's not very dramatic or compelling. It also calls into question whether Andrea's book, unread by me, is as lacking in autobiographical inquiry as a Duras' roman a clef exults in the stuff.

But as she tells him at one point in the film, trying to exhort the lad to write, ``You've got a great subject: Me!'' The resulting, warts-and-more-warts portrait does not lack detail on that great subject, but the film does smack - with its preponderance of scenes in which Duras drinks, suffers delusions, grouses, manipulates and has a hard time writing herself - of shadow-dweller's vengeance. (Andrea finally got around to writing the book several years after her death.)

Yet such foibles make for great, playable behavior, and an actress as accomplished as Moreau easily makes them the building blocks of a sympathetically nuanced characterization. Even at her lowest, it's impossible to feel pity for the powerful, independent and fundamentally generous spirit of Moreau's Duras. And that's apparent from the first time she opens her door to the feckless man-boy who fulfilled so many of her needs.

CET AMOUR-LA - Three stars

(Not rated: language, nudity, substance abuse, mild violence)

Starring: Jeanne Moreau, Aymeric Demarigny.

Director: Josee Dayan.

Running time: 1 hr. 38 min.

Playing: Laemmle Music Hall, Beverly Hills.

In a nutshell: A terrific performance by Moreau as Marguerite Duras is enough to recommend this otherwise unenlightening film about the writer's relationship with a man half her age.