Renée Fleming: Gorgeous banality

Gown by Gianfranco Ferre, watch by Rolex, Grammy-award-winning recordings by Decca: Renée Fleming is fast becoming an industry – a living, breathing, singing endorsement. Night Songs, the recording of the recital that was performed at London's Barbican on Sunday marks the start of what could become a highly marketable partnership with pianist Jean-Yves Thibaudet. It's stamped with all the requisite hallmarks of glamour. Thibaudet is more than a match for Fleming in the couture stakes. He's French, he's photogenic, and he's a fine pianist, too. Yes, this recital could run and run.

So, "Night Songs" – songs of love, pain, mystery, desire in the small hours. Renée Fleming behaving badly? Not badly enough, I have to say. The "seductiveness" of this recital was entirely cosmetic. Fleming's lustrous soprano is an instrument of ravishing, of infinite possibilities. So how is it possible that by the interval, I was beginning to feel that I had already heard enough for one evening? How is it possible to tire so quickly of so gorgeous a sound?

Quite simply because it's turning into a one-colour voice. Style is taking precedent over content. It's starting to mean less and less. Fleming has always made free with the portamento – the slides that can lend enticement and enchantment to the line – but these days their deployment is turning her into something of a crooner. A set of songs by the rarely performed Austrian Joseph Marx set the tone for the evening with Fleming scooping and swooping, mooning seductively around texts with a penchant for the word "fragrant". Fragrant is right. But already this tiny mannerism was turning to big-time affectation.

The second song, "Nachtgebet", was interesting inasmuch as the piano harmonies were uncannily close to jazz. Crooning was somehow appropriate. "Selige Nacht" brought one huge dynamic contrast – a sudden flood of longing – which was exciting in an extravagant, operatic kind of way, but disproportionate in context. And there you have part of the problem. Indulgence in the moment, at the expense of the whole. It is possible to convey the awesome stasis of Strauss's "Ruhe, meine Seele!" without actually grinding to a halt. "These are overwhelming times," reads the text. "Heart and brain are sorely tried." They are if we lose all sense of the musical line.

In the last stanza of "Leise Lieder" ("Soft Songs"), it was hard to appreciate the effect of whole phrases, because of the unwarranted attention lavished on individual notes. And those notes inevitably said more about Fleming than they did about the song. Perhaps the best thing she sang all evening was Strauss's "Cacilie" because she let the song, and the voice, go. Carried by its impetus "to blissful heights", she managed a glorious and liberating ascent to the high B, and real value for money on the final note. The capacity crowd hung on to that with relish.

The centrepiece of the programme was Debussy's "Chansons de Bilitis", whose tone was limpid and idiomatic, thanks to some exquisite texturing from Thibaudet. From Fleming's point of view, a certain detachment worked in her favour here, the artfulness of her singing finding kinship in the artfulness of Pierre Louys's words and Debussy's languorous music. Even so, some of the detail was still too self-consciously applied. It was interesting to compare her very atmospheric, but very calculated glissando in the final line of "La chevelure" with Thibaudet's breathtakingly spontaneous diminuendo from the clinching starburst of Debussy's "Feux d'artifice". With Thibaudet, you weren't at all conscious of the technique. The effect was as sparkly as the buckles on his shoes.

But by this point Fleming's singing had, to this pair of ears, melded into an all-purpose blur of gorgeousness. The final group of Rachmaninov songs had nothing whatever to do with Rachmaninov. She might still have been singing in French, for all that the Russian texts made any impression. The darker hue, the Slavic ache, the emotional fibre of these wonderful songs completely eluded her. Instead, she gave us a kind of purple vocalise.

The first of her encores – "Marietta's Lied" from Korngold's opera Die tote Stadt – which she can, and should, sing as well as anyone in the world today, was again disfigured by self-regarding rubatos. If it's possible for an operatic aria to sound like a photo opportunity, then this was it, complete with diva-like poses struck in that black-and-cerise Ferre wrap. But beauty is, of course, only skin-deep – and so was this recital.

'Night Songs' (Decca) is released on 28 Jan