perfume
芬 centers on a pleasant, sweet smell: perfume or fragrance. It is the idea of a scent that spreads and is noticed.
芬 combines the plant radical 艹 with 分, which likely contributes the sound and the idea of something spreading or dividing, suggesting a scent that spreads from plants.
Plants 艹 that divide 分 their fragrance into the air: 芬 is perfume.
For フン, imagine a fun perfume that makes everyone smile: fun -> フン, and the scent spreads from the flowers.