Notre-Dame-du-Bourguet co-cathedral, also known as Notre-Dame du Marché, stands in the heart of Forcalquier in the Alpes-de-Haute-Provence department. Built in the 12th century, it was established as the co-cathedral of the diocese of Sisteron in 1408. Its central nave, choir, transept, and the base of its bell tower dating from the beginning of the 13th century constitute the first attempt at adapting Gothic art in Pays d'Oc. The second floor of the bell tower was redone in the 17th century in a mix of Romanesque and Gothic, illustrating the religious architecture of Provence and testifying to the long history of the County of Forcalquier. Listed as a Historical Monument since 1914, the cathedral was selected in 2019 to benefit from the restoration fund of the Heritage Lottery.