Here's a couple of interesting adresses in Rome.
Profumum Durante Roma
Via Della Colonna Antonina, 30 (Between Pantheon and Via del Corso)
Artisanal perfume from Rome, I've sampled the following:
Acqva di Sale: Marine scent with some fruits and cedarwood. Not my cup of tea, but the SA said it is their best seller.
Ichnvsa: Lovely fig scent, both leaves and wood used. Other ingredients are herbs and mirto(blueberry). Absolutely wonderful! Creamier and not as sweet as Philosykos and the mirto in the middle gives a nice twist to it. The initial notes are much more herbal than Philosykos. A real winner!
Santalvm: Sandalwood and cinnamon, I'm not a big fan of cinnamon, but Sandalwood lovers will surely appreciate this one.
Fvmidvs: Vetiver, a very, very strong earthy take on a vetiver. I haven't got anything to compare it with, it's nothing at all like the fresh Guerlain or the soapy Creed I know.
Very good stuff overall, all smelling very natural. They only sell their perfume in their own shops but if someone is interested, send them an email. Only 100ml for 130 euro in EDP strenght. They also carry Creed, LV, Carthusia, Different Company, L'artisan, Keiko Mecheri, Diptyque and Frederick Malle. Maybe also some others.
Piazza San Lorenzo in Lucina 5 (just off Via del Corso)
Very nice old pharmacy with a very nice stock of LVs, Creeds, Kiehls etc, (one of) the most famous in Rome.
Officina Profumo Farmaceutico Santa Maria Novella
Corso Rinascimento 47 (near Piazza Navona)
Rome branch of the original SMN pharmacy in Florens, great potpourri, soaps etc
Tad Concept Store
Between the Spanish Steps and Piazza del Popolo
Bond no 9s, CdGs, Carthusia, Miller Harris.
Via Lungaretta (Trastevere)
My personal favorite, carrying most of the famous french, italian and english artisanal brands.
Via di Ripetta 34 (Tridente area)
Pefume bar, doesn't sell anything but you can sample stuff and get directions where to go to buy it later.
Diptyque, Coudray etc
Along Via Nazionale and around Santa Maria Maggiore you can find a couple of Discount stores. There is a Sephora at Termini, the main train station, but it isn't very good.
There are lots of shops selling niche stuff near the Pantheon (Campo Marzio area). Just walk around, here you will also find a fashion store for men called Degli Effetti that stocks the Dior limited edition line.
On every other block in the city centre there is a profumeria selling designer stuff. Sometimes at the big flea market, Porta Portese, there is a stand that sells testers and old stock. Sometimes you can find Creeds and Etros really cheap. I never bought anything from here so I can't really say if it's a good deal or not.
Somewhere between Via del Corso and the Spanish Steps there is a store selling discontinued scents (maybe Via Frattina?).