On Gauls/Celts:
"The earliest Celts who were major players in the classical world were the Gauls, who controlled an area extending from France to Switzerland. It was the Gauls who sacked Rome and later invaded Greece; it was also the Gauls that migrated to Asia Minor to found their own, independent culture there, that of the Galatians. Through invasion and migration, they spread into Spain and later crossed the Alps into Italy and permanently settled the area south of the Alps which the Romans then named, Cisalpine Gaul.
The Gauls were a tribal and agricultural society. They were ruled by kings, but individual kings reigned only over small areas. Occasionally a single powerful king could gain the allegiance of several kings as a kind of "over-king," but on the whole the Gauls throughout Europe were largely an ethnic continuity rather than a single nation.
Ethnic identity among the early Gauls was very fluid. Ethnic identity was first and foremost based on small kinship groups, or clansthis fundamental ethnic identity often got collapsed into a larger identity, that of tribes. The main political structures, that of kingship, organized themselves around this tribal ethnic identity. For the most part, the Gauls did not seem to have a larger ethnic identity that united the Gaulish world into a single cultural groupthe "Gauls" as an ethnic group was largely invented by the Romans and the Greeks and applied to all the diverse tribes spread across the face of northern Europe. The Gauls did have a sense of territorial ethnicity; the Romans and Greeks tell us that there were sixteen separate territorial nations of Gauls. These territorial groups were divided into a series of pagi, which were military units composed of men who had voluntarily united as fellow soldiers.
The Gauls, however, were not the original Europeans. Beginning in an area around Switzerland, the Celts spread westward and eastward displacing native Europeans in the process. These migrations begin around 500 BC. The Gaulish invasion of Italy in 400 was part of this larger emigration. The Romans, however, pushed them back by the third century BC; native Europeans in the north, however, were not so lucky.
Two Celtic tribes, the Cimbri and the Teutones ("Teuton," an ethnic for Germans, is derived from the Celtic root for "people"), emigrated east and settled in territory in Germany. The center of Celtic expansion, however, was Gaul, which lay north of the Alps in the region now within the borders of France and Belgium and part of Spain.
The earliest account of the Gauls comes from Julius Caesar. In his history of his military expedition first into Gaul and then as far north as Britain, Caesar dexcribed the tribal and regional divisions among the Gauls, of which some seem to have been original European populations and not Celtic at all. "
So it seems that Celts/Gauls is interchangable when considering Mainland Europe.
But equating Gauls=French is incorrect, just as equating Huns=Germans.