I’m sorry, but naming your daughter Charlemagne gives the impression that you are very poorly educated. At the least, you certainly don’t know much about European history. Awful, awful, awful on a girl.
For a boy, Charlemagne is like naming your son [name]Napoleon[/name] or [name]Julius[/name] [name]Caesar[/name]. You might could get away with it as a middle name, but it’s entirely too pretentious as a first name.