Teen-ager's coming of age

Jeanne Moreau is best known as the star of countless French movies, including such classics as ''Jules and Jim'' and ''The Lovers.'' A few years ago she became a director as well, making her debut with ''Lumiere,'' a drama with a distinctly feminine sensibility. Now her second directorial effort has opened on American screens: L'Adolescente, a memory movie about a teen-age girl's coming of age.

It seems that every French filmmaker has made at least one picture about his or her bittersweet youth, recalling a time when life seemed both simpler and more perplexing. Moreau's contribution focuses on an adventurous girl spending the summer at a farm with her knowing grandmother (Simone Signoret) and her parents. Here she finds herself surrounded by all manner of people, from a sensitive physician to an unwed mother who has become a dubious neighborhood institution. Little by little, our heroine gets to know them and tries to plumb their mysteries.

As I observed when ''L'Adolescente'' had a limited New York engagement in 1979, Moreau's filmmaking touch is delicate even when the plot occasionally leaves taste and restraint behind. Though some of the characters may be rough, their treatment is rarely rude; and despite lapses into trite family portraits and artificially fizzy images, ''L'Adolescente'' generally makes the most of its nostalgic format. At its best, the action seems to glow with its own inner light while remaining brash and buoyant. One looks forward to seeing what the multitalented Moreau comes up with next.