Some thoughts on this profile:
1. We have him as Carlos / Charles. The Geni naming conventions advise using the modern form of the name in the territory where the person lived. This Charles lived in what is now France. The modern French form of his name is Charles. Carlos is the Spanish form of Charles, but this Charles had no association with Spain. So, I recommend moving Carlos to the AKA field.
2. We have him as "IV Duke of Maine, King of the Franks". The conventions advise using only the highest title in the name fileds, and moving all subsidiary offices and titles to the About Me. So, we could remove IV Duke of Maine.
3. There is an ambiguity of "IV Duke of Maine", because some people like the pseudo-antique Roman numbers for order for succession, while others prefer the modern form of using Roman numbers for ordinals and Arabic numbers for order of succession. So, does this mean he was Charles IV, Duke of Maine? Or that he was Charles, 4th Duke of Maine?
In fact he was neither. He didn't have the actual title "Duke of Maine". Instead, he had the title "rex Francorum" (King of the Franks) and he ruled the ducatus Cenomannicus, 790-811, an area that later became the duchy of Maine. He was the third known ruler of that area, and the first named Charles.
http://en.wikipedia.org/wiki/Charles_the_Younger
http://en.wikipedia.org/wiki/Counts_and_Dukes_of_Maine
4. As King of the Franks, he was co-king with his father 800-811. That is, he was "young king", his father's designated successor. Genealogists have dealt with this a variety of ways. I've seen him called (a) "co-king of the Franks", but also (b) "king of the Franks at Le Mans" (the capital of Maine), even though he was king throughout his father's domains, and (c) "king of Neustria", because the ducatus Cenomannicus was an alternative name for the regnum or kingdom of Neustria.
http://en.wikipedia.org/wiki/Neustria
5. His current surname on Geni is "de Neustrie". I suggest changing to "des Francs" or "of the Franks" -- unless we change his title to King of Neustria. Neustrie / Neustria is a remnant of the foregoing problem with his title.
6. There is a typo in the name field. His mother is called Hildergard. Should be Hildegard.
7. The AKA field gives an alternative name Liderie, and the occupation field calls him (in various forms) Forester of Flanders and Harelbeke. It looks like this profile was merged at some point with a profile for Lidéric or Lydéric, one of the legendary Foresters of Flanders. These should be deleted.
http://en.wikipedia.org/wiki/Lyd%C3%A9ric_and_Phinaert
http://sbaldw.home.mindspring.com/hproject/prov/baldw001.htm
8. Similarly, we should delete some of his other names and titles: King of the East Francs, Prince, du Buc, and Roi de Bretagne.