Guerin, Garin, Warin, or Werner (Latin: Werinus or Guarnarius; died 845 or 856) was the Count of Auvergne, Chalon, Mâcon, Autun, Arles and Duke of Provence, Burgundy, and Toulouse.
His proximity, in extant documents of the time, to Bernard of Septimania has been used as evidence for a relationship to that family, as has the existence of a related "Count Guerin" in later charters of the 850s and 860s.
In 819, he and Berengar of Toulouse invaded Gascony to put down a rebellion of Lupus III Centule, as recorded by both the Annales regni Francorum and the Vita Hludowici.
[4] On 24 July 840 in Strasbourg, Lothair precipitated a new civil war by declaring his imperium over all the lands of the empire and, joining with his nephew Pepin II of Aquitaine, attacked the Loire Valley.
While Ermenaud III of Auxerre, Arnulf of Sens, Audri of Autun, and Gerard II of Paris pledged themselves for Lothair, Guerin and Adalbert of Avallon remained with Charles the Bald.
On 25 June 841, Lothair and Pepin initiated the ensuing Battle of Fontenay and had the upper hand until the arrival of Guerin and his army of Provençals turned the tide in favour of Charles.