There is nothing wrong with a fasting person smelling good smells, from food, perfume etc, but he should not inhale bukhoor (incense) or the steam coming out of the cooking pot because these have particles which may reach his stomach.
It says in Haashiyat al-Dasooqi (1/525):
If the smoke of bukhoor or steam from the cooking pot reaches the throat, the day must be made up… if it reaches it through inhaling deliberately, whether the one who does that is the one who is making it or someone else. But if one of them reaches the throat without him wanting it to, then he does not have to make it up, whether he is the one who is making it or someone else according to the correct view