Iris is a note of much contention within niche perfume circles. The issue is what, exactly, this note smells like. Some feel it is best represented by Orris root, which yields its aroma differently from the flower. Fabienne Pavia, in her book The World of Perfume, claims Orris root resembles the scent of violets. Dane from Pere de Pierre likens it to carrots (and thinks Infusion d'Iris is nice, but unnatural-smelling). To the question, "What does the flower Iris smell like?", WebAnswers posits a broad response: pleasant flowers. It seems there is little consensus on this.
Infusion d'Iris doesn't smell particularly natural, and I wouldn't go as far as to say this should be a "reference Iris" perfume, but it is a very good rendition of the powdery, rooty essence of Orris, mingling with the sweet touch of Iris flower. Let me boil this down to the simplest explanation possible - Infusion d'Iris is very powdery. From the outset there's a blast of desiccated citrus, sharp orange and bergamot, followed by a cool, silky floral note. This stage reminds me of the iris in Green Irish Tweed, which is a dull, slightly floral note. Let not the snobs tell you iris can't smell floral, for it often does, and there's nothing remotely absurd about that, nor is it wrong to openly observe it. There is such a thing as an iris flower, after all, and certain kinds do smell nice.
After the silky interlude comes a darker, earthier element, built of vetiver, incense, cedar, and benzoin, which lends the composition a slight warming effect. Beyond these things, all my nose detects is dry, earthy powder. It's beautiful in its own right, although not a perfume I'd reach for very often. There is something very poised and stiff about Infusion d'Iris, and it doesn't match my personality. It's better for businesswomen, as all women in the white collar world need an elegantly uninviting fragrance - a perfume to command respect with. This does the trick nicely.
I'll stick to the silky coolness that thrums through the shadowy heart of Green Irish Tweed, although if I'm looking to switch off with another unisex iris, I know where to go.