Commentary
Charles Cawley: "She was the sister of Geoffroy and sister-in-law of Théobald de Nyon"

Europäische Stammtafeln [= ES] (Schwennicke, 1978), Band III, Teilband 4 (1989), gives the wife of Guigo/Guigues de Vion [Vienne] as Fredeburga, sister of Geoffroi and sister-in-law of Théobald de Nyon.

if true then she could NOT be the daughter of Richard of Vienne and granddaughter of Charles Constatine.
Family
ClaimDetailEvidence
Spouse 1stGuiges I (e949-996) 
Child +Guiges II (e972-~1009) [S3198]
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Attributes
ClaimDetailEvidence
GenderFemale
NameFredeburga [S2253] [S3198]
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NameFriburge [S2253]
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NameFribourge [S2253]
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Timeline
ClaimDateDetailAgeEvidence
Birthest 950 (947-953)
 
LivingMar 26, 1027 [S2253]
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Sources
IndexTitle
[S2253] Stone, Don, "Medieval Genealogy Newsgroup: Descents from Charles Constantine?" (GEN-MEDIEVAL Mailing List, Feb 2017) (http://archiver.rootsweb.ancestry.com/th/read/GEN-MEDIEVAL/2017-02/1486267144).
[S3198] Cawley, Charles, "Foundation of Medieval Genealogy (Medieval Lands - Burgundy Kingdom: Viennois)" (https://fmg.ac/Projects/MedLands/burgkvien.htm).