Caussou (French pronunciation: [kosu]; Occitan: Causson) is a commune in the Ariège department in the Occitanie region in southwestern France.

From the early thirteenth century for the next 7 or 8 decades, Caussou was greatly affected by the Inquisitions and saw many of its inhabitants forced to wear the Yellow cross - the punishment sign of the heretics.

It was in 1322 in the Caussou garden of Béatrice's uncle Pons de Planisoles, that her cousin Raymond and an accomplice by the name of Bourret buried the body of a shepherd that he had murdered.

The aristocratic Raymond was never charged with the murder, but the hapless Bourret was hanged for the offence at Foix.

At his trial in an attempt to reek revenge, Bourret had implicated one of Béatrice's brothers Bernard as a Cathar heretic; as a result, on 4 July 1322, Bernard, who still lived at Caussou, was sentenced to wear the Yellow cross by the Inquisition.