He specialized in studying the Roman city of Lugdunum, known in modern times as Lyon, France.
In 1952, he succeeded Pierre Wuilleumier in directing the dig at the Roman archeological site of Fourviere, and found several major monuments in the ancient Roman city of Lugdunum (Lyon) including the Odeon of Lyon, Cybel Sanctuary, and the Amphitheater of the Three Gauls.
Audin also made multiple fortuitous discoveries in the districts of Vaise and the fifth arrondissement of Lyon.
In 1968 he was the first to observed a section of a Roman rampart, which in 2012 was confirmed to be part of the Murus Gallicus of Lyon.
As the conservator of many Gallo-Roman artifacts from Lyon, he convinced the mayor Louis Pradel to construct a museum to house them.