It depends where the smell originates.
Using fragrance only masks the smell... it doesn't remove the source of the smell.
If the smell is coming from the 排水位, then pour some 1:99 water-bleach solution.
If it is coming from the toilet bowl, then use the kind of cleaning product that washes with every flush (either attaches to the side of the bowl, or hanging inside the toilet box).
If it is coming from moist towels, then use de-humidifier.
I think it's important to find out what is the source of the smell first.....