Welcome to basenotes!
I noticed that you are in Mexico. I was in Cancun last month and went perfume shopping down at your malls for tourists. There you can find many perfume stores (high end) and most of them carry the Guerlains.
Guerlain is my favourite house. They are made with mostly natural ingrediants. What's wonderful about them, especially with the vintage or older ones, like Mitsouko and L'heure bleue, is that you can spray them on and they will work with your body chemistry. The initial spray, you will smell certain notes, but as the hours go by, the smell will change.
I once tried the L'heure Bleue EDT on one wrist and the same pure parfum version on the other wrist. Wow, did I ever notice the difference. Right away, the EDT wrist evolved and within the hour, it flattened out to the base notes -- smell lasted maybe 4 or 5 hours on me. The pure perfume, I didn''t get the initial blast -- what I got was the smoother top note, which evolved over time 3 or 4 hours to the final notes. After 8 to 10 hours, I can still smell the base notes. From then on, I was hooked and will purchase only the parfum if I can get it and afford it -- you need only a tiny spray to get this effect.
Guerlain is not expensive compared to others, especially the niche fragrances. In Mexico, expect to pay about $30-$60US (in the stores for tourists) for 50ml of the EDT or EDP.
Hope this helps.