Generally, when a person smells a fragrant fruit, he first recites the Beracha of "Ha’noten Re’ah Tob Ba’perot." However, Rabbi Moshe Halevi (Israel, 1961-2001) writes in his work Birkat Hashem that one who smells a lemon does not recite this Beracha, but rather the Beracha recited before smelling other fragrant substances – "Boreh Mineh Besamim." Based on a responsum of the Hida (Rav Haim Yosef David Azulai, 1724-1806), in his work Yosef Ometz (24), Rabbi Moshe Halevi explains that a lemon’s fragrance is emitted not by the fruit itself, but rather from its peel, and thus one should not recite the Beracha over the fragrance of fruits.
Hacham Ovadia Yosef, however, citing the Ginat Veradim, disagrees. He writes that as long as the peel is still attached to the lemon, we consider the lemon a fragrant fruit, and thus one recites "Ha’noten Re’ah Tob Ba’perot." This ruling appears in Yabia Omer (vol. 9), and in Hazon Ovadia – Berachot (p. 309). Hacham Ovadia even writes that he followed the practice of smelling lemons every Shabbat with the Beracha of "Ha’noten Re’ah Tob Ba’perot," in order to fulfill the requirement of reciting one hundred Berachot each day. (This requirement is difficult to observe on Shabbat, when the Amida contains only seven Berachot, and thus Hacham Ovadia would find ways to make up the missing Berachot, such as by smelling a lemon.) He agrees, however, that if one smells a lemon peel that was removed from the fruit, he recites "Boreh Mineh Besamim," since he is smelling a peel, and not a fruit.
It should be noted that although some people recite the text of "Asher Natan Re’ah Tob Ba’perot" (in the past tense) when smelling fragrant fruits, the correct text is "Ha’noten Re’ah Tob Ba’perot."
(Based on Yalkut Yosef – Berachot, p. 332)
Summary: Before smelling a lemon, one recites the Beracha, "Ha’noten Re’ah Tob Ba’perot." If one smells a lemon peel that was detached from the fruit, he recites the Beracha, "Boreh Mineh Besamim."
