The "Temple of Janus" is a Romano-Celtic religious structure located in Autun, Saône-et-Loire, France, to the North-West of the ancient city of Augustodunum.

The site's history dates back to Neolithic times and underwent an important phase of monumental construction in the 1st century CE.

[1] It sits beside a road that passed through the Arroux gate, crossed the river, and headed West towards Lutetia (Paris), the valley of the Loire, and Cenabum (Orléans).

[2][3] The site sits at an average altitude of 290 meters, atop a plateau that gradually slopes downward towards the valleys of the Arroux to the South and the Ternin, one of its tributaries, to the East.

[5] Geophysical exploration and aerial photography have demonstrated the existence of a vast Neolithic enclosure, accompanied with layouts whose functions are ill-defined.

The deity venerated here remains totally unknown.The cella was built with a nearly square footprint (16.80 x 16.35 m) and its elevation reaches up to around 24 meters, a record for Gaul.

The surface of the walls is entirely made up of small, square sandstone rubble with no terracotta inclusions, and the putlog holes that had supported the scaffolding are still visible.

[18] The exterior of the walls featured four rectangular niches and three small openings crowned with stone discharging arches 13 meters above ground, which illuminated the interior of the cella.

[22] Studies undertaken in 2012 revealed the existence of two successive and concentric ambulatories, the older, perhaps featuring a portico, could have been connected to the Temple of Janus or an earlier religious structure.

[23][24] In 1871, Jacques Gabriel Bulliot undertook excavations to the North-West of Autun and around the temple which provided the basis for a detailed map drawn by Jean Roidot-Déléage.

[28] Aerial surveys led by René Goguey in 1976 resulted in the discovery of the Haut-du-Verger theater,[29] allowing the collection of sparse information obtained on the district, which has since been seen as a vast peri-urban sanctuary having "the function of uniting different cults of the city".