Commentary
She may have been the daughter of Guillaume III “Tête d'Etoupes” Duke of Aquitaine / Guillaume I, Count of Poitou & his wife Adela.

Charles Cawley: 'There is some doubt about Adelais´s ancestry. The 11th century Translatio S. Maglorii et aliorum names "Adelaide…filia Pictavorum comitis, de progenie Caroli Magni" as the wife of "Hugone, Francorum duce", clarifying that the latter refers to Hugues "Capet" King of France when it names "Roberto…rege, memorati ducis filio". This Poitevin origin is also suggested by Richer when he records that King Robert "ob nepotem suum Wilelmum" besieged "in Aquitania…Hildebertum". It is assumed that such a relationship between King Robert and Duke Guillaume would be through the king's mother as no family connection through his father has been established. Some doubt about this supposed Poitevin ancestry is introduced by the Chronicle of Ademar de Chabannes which, on the other hand, recounts the dispute between "Dux Aquitanorum Willelmus" and King Hugues, as well as the subsequent peace agreed between the parties in 990, without mentioning that the duke was the king's brother-in-law, all the more surprising if the Poitevin origin is correct as Ademar concentrates on Poitevin affairs and also includes genealogical details in his narrative. Another possible ancestry is suggested by Helgaud's Vita Roberti Regis which names "Rex Francorum Rotbertus…patre Hugone, matre Adhelaide", specifying that "ab Ausonis partibus descenderat". Settipani equates "Ausonia" with Rome or Italy, although no other reference to an Italian origin for Adelais has yet been identified. The Chronicle of Alberic de Trois-Fontaines refers to the mother of "rex Francorum Robertus" as "superiorem regum Anglie soror", but it is difficult to see to whom this could refer or how it could be correct. The paucity of references in contemporary sources to the wife of Hugues Capet and her origin contrasts with the frequent references to his mother and to the wives of his son King Robert II. This suggests that the background of Queen Adelais may have been obscure and that her family had little political influence at the time, although this would be surprising as her husband already enjoyed a position of some power at the Carolingian court at the time of his marriage. Maybe her family was prominent when the couple married but suffered a subsequent decline by the time her husband was elected king. Nevertheless, an Aquitainian marriage would have fitted the political circumstances of the time. After several decades of dispute between the Capet and Poitou families, a permanent peace appears to have been established from about the time the marriage took place.'

Stewart Baldwin says as much.
Family
ClaimDetailEvidence
SpouseHugh Capet, King of France (~941-996) 
Child +Hedwige de France (~969-) [S756] [S2720] [S2727]
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Child +Gisela de France (~970-) [S2727]
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Child +Robert II, King of France (972-1031) [S756] [S922] [S2727]
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Attributes
ClaimDetailEvidence
GenderFemale
NameAdelaide [S1469]
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NameAdelaide of Poitou [S756]
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NameAlice of Poitou [S756]
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NameAdelais [d'Aquitaine] [S921]
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NameAdelais d'Aquitaine [S922] [S2720]
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NameAdelais de Poitou [S929] [S2727]
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NameAdelaide [de Poitou] [S2727]
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Possible fatherGuillaume III, Duke of Aquitaine (e912-963) [S756] [S929] [S2727]
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Possible motherAdela de Normandie (e897-<=971) [S756] [S929] [S2727]
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Timeline
ClaimDateDetailAgeEvidence
Birthabt 945France [S756]
Cawley gives her birth as 950-954, but she sou;d have been very young at her marriage
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Marriageabt 968 (bef 969)Hugh Capet, King of France (~941-996) [S756] [S929] [S2727]
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Deathabt 1004 [S756] [S929] [S2727]
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Sources
IndexTitle
[S756] Weis, Frederick Lewis, "Ancestral Roots of Sixty Colonists Who Came To New England before 1700, 7th Ed." (Genealogical Publishing Co., Inc., Baltimore, 1999).
[S921] Cawley, Charles, "Foundation of Medieval Genealogy (Medieval Lands - Northern France: Artois, Boulogne)" (2006-7 (v1.2 Updated 21 January 2007)) (https://fmg.ac/Projects/MedLands/NORTHERN FRANCE.htm).
[S922] Cawley, Charles, "Foundation of Medieval Genealogy (Medieval Lands - Burgundy Kingdom: Kings)" (2006-7 (v1.1 Updated 08 September 2006)) (https://fmg.ac/Projects/MedLands/BURGUNDY KINGS.htm).
[S929] Cawley, Charles, "Foundation of Medieval Genealogy (Medieval Lands - Aquitiane Dukes)" (2006-7 (v1.3 Updated 18 July 2007)) (https://fmg.ac/Projects/MedLands/AQUITAINE.htm).
[S1469] Baldwin, Stewart, "The Henry Project - Adélaïde" (July 26, 2008) (https://fasg.org/projects/henryproject/data/adela002.htm).
[S2720] Cawley, Charles, "Foundation of Medieval Genealogy (Medieval Lands - Hainaut)" (v4.6 Updated 03 February 2020) (https://fmg.ac/Projects/MedLands/HAINAUT.htm).
[S2727] Cawley, Charles, "Foundation of Medieval Genealogy (Medieval Lands - France, Capetian Kings)" (v4.3 Updated 07 January 2020) (https://fmg.ac/Projects/MedLands/CAPET.htm).