1) It is prohibited for a male to [intentionally] smell the perfume that is on a [forbidden] female. (Shulchan Aruch Even HaEzer Siman 21:1. See also Mishna Berura Siman 217:17)
According to some Rishonim this is a biblical prohibition. (See Rambam Pirush Hamishnayos Sanhedrin Perek 7 on Mishna on 54a and Sefer Chareidim Perek 28 quoting the Tashbatz. They say that the prohibition of “Lo Tin’af” is also read “Lo Tehene L’Af, do not have pleasure with your nose”. See also Sefer Chareidim perek 15 that there is an additional prohibition of “Lo Tikrevu L’Galos Ervah” as anything that causes one to get closer to transgressing Arayos is biblically prohibited.)
2) Perfume on a girl below the age of twelve, according to some Poskim it may be smelled while others are stringent and disallow this as well. (See Mogen Avrohom Siman 217:10 and Mishna Berura S”K 16)
Taken from halachafortoday.com
Some Poskim even prohibit a man from smelling his wife’s perfume on her when she is a Nidah. (Mishna Berura ibid.)