I think moderation is key...forcing people to not wear any frangrances sounds like elementary school. Adults should decide for themselves what's right for them, as long as they are willing to avoid overly aggressive smells and moderate the amount.
I think that this can enter the clothing guideline a company has the right to put in place so yes bosses have the right to tell their employees to not use perfumes or anything else that has a fragrance while at work. On the other hand just because you have an allergy does not mean that you can dictate what others do near or around you. I am allergic to nuts and never have I forced anyone to not eat nuts and if there's a nut scent out there I do not want anyone stopping themselves from wearing it around me either, one time when I was on a subway a man was eating a bag of nuts and the smell was bothering me and I just got up and sat elsewhere.