(actually I knew this long ago, but feel a bit dramatic at the moment.)
The idea of a perfume capturing a moment, or an hour in time as a universal constant holds great appeal to me. Living in the moment, yes, that's a very good thing to do. However, there is pleasure of a different order in the capture of a period of time, a mood, an emotion... and L'Heure Bleue seems to me to do this very well.
So well, in fact, that I cannot yet put words to what L'Heure Bleue smells like. Notes, yes, I can describe. Sillage, yes, and longevity, that too. But L'Heure Bleue confounds and confuses the senses in a way that, perhaps a Zen Koan does.
That is the essence of what I want to say about L'Heure Bleue.
I may say more later, if I acquire a different concentration of L'Heure Bleue...but what I have said here may suffice.