FOR A MUSICAL containing the effervescent "The Night They Invented Champagne" and several other sparkling standards, the Broadway-bound adaptation of Lerner and Loewe's "Gigi," now at Baltimore's Lyric Opera House, is strangely flat.

The reason for this staging (aside from the fact that resurrecting these vintage shows is fashionable and profitable) seems to be the availability of Louis Jourdan, who played the roguish playboy Gaston in the 1958 movie. Now, more than 25 years later, Jourdan is reunited with "Gigi" -- but in the role of adorable uncle Honor,e, "a collector of beautiful young things," indelibly played in the movie by Maurice Chevalier.

A veteran charmer himself, Jourdan doesn't attempt to remake the role so much as to recreate it, twinkling away merrily a la Maurice. But the actor, at 63, is disconcertingly young- looking to play the part of the aging boulevardier, which becomes most apparent when Jourdan croons his half of the dotty duet "I Remember It Well" to Taina Elg, who is made up to look like Jourdan's grandmother.

Adapted from a short novel by Colette, "Gigi" is set in the rarefied air of turn-of-the- century Paris society. Like Gigi's Aunt Alicia, the Colette story has "changed hands more often than Alsace-Lorraine" in its transition from novel to French film, to stage play to movie musical to Broadway show, becoming on the way a frothy, weightless story of a saucy young sprite, descendant of a long line of expensive coquettes, now being trained by her mercenary aunt and grandmother as a continental Cosmo girl, a professional flirt and jewelry shark. Gigi unwittingly captures the heart of heartless playboy Gaston and, since this is an American musical comedy, decides she'd rather be married than kept.

Dark of eye and brassy of voice, Lisa Howard is a properly enchanting Gigi, balancing between impish child and chic young woman. And as her suave swain Gaston, Tom Hewitt fits the definition of "dashing." Betsy Palmer is funny as Alicia, but speaks an odd hybrid tongue, wandering capriciously back and forth between Westchester County and the Left Bank. Lerner and Loewe's recitative songs receive polite treatment from the entire cast, but the use of microphones allows everyone to play their parts too small.

Everyone, that is, but Joe Gustern, who shows what this show could have been, filling the hall with melody and personality in true musical comedy style in his too-brief scene as Gaston's lawyer.

Jeffrey Schneider's stylized sets are an attempt at an Art Nouveau/Paris Metro fantasy, with swirling panels of stained glass revolving and descending for scene changes. Each setting looks like the others, though, and the muddy aquas, purples and greens clash with Dean Brown's antiseptic, ice-cream-colored costumes.

Though she's lost a little fizz, sweet-natured, airheaded "Gigi" has changed little since her birth in the '50s, for better or worse. GIGI -- At Baltimore's Lyric Opera House through January 5.