What was the capital roman gaul

There was not acapital of Gallia (Roman Gaul).

From its conquest in 50 BC to 314 AD Gallia was divided into threeRoman provinces. Each had its own capital. The capital of GalliaNarbonensis (the south of France) was Narbo(Narbonne). To start with, the capital of Gallia Aquitania (thesouthwest of France up to the river Loire) was MediolanumSantonum (Saintes). Later it was moved toBurdigala (Bordeaux). The capital of GalliaLugdunensis (central France) was Lugdunum (Lyon).The capital of Gallia Belgica (Belgium, Northern France up to closeto the river Seine, north-eastern France and the French speakingpart of Switzerland) was Augusta Trevorum(Triers).In 314 the emperor Diocletiansubdivided Gallia into 13 new and smaller provinces. He alsogrouped them into two Dioceses. These were new administrative unitswhich oversaw a group of the new provinces. The two dioceses werethe Diocese of Galliae (northern and eastern France and Frenchspeaking Switzerland) whose capital was AugustaTrevorum, and the Diocese of Viennensis (southern France)whose capital was Vienna (Vienne). Later theDiocese of Viennensis was renamed Septem Provinciae (SevenProvinces).Diocletian also included theprovinces of Germania I (formerly Germania Superior) and GermaniaII (formerly Germania Inferior) into the Diocese of Galliae. Notethat Galliae is the plural of Gallia and therefore the Diocese ofGallie meant the Diocese of the Gauls.