Pre-Roman Gaul population: at least 100 million, I guess

Context: in his Commentaries on the Gallic War, Julius Caesar frequently exaggerates the number of enemy troops he was facing, unless one is to believe that nearly every tribe and city-state in Gaul and western Germany was able to field armies of 50-100k or even more (with some of the German tribes also barely practicing agriculture according to Caesar) to square off against the Romans.

The most outrageous example of this by far is a battle in which Caesar claims his force defeated *430,000* soldiers without taking a single casualty, although this is so ridiculous even by the standards of the work that I’m inclined to think it must be a scribal error.

Caesar’s casualty reports always read like he was fighting the entire respawning player base of Europe

Now I understand why in many fictions there are tribes of barbarians that live in desolate lands with little agriculture and they somehow field massive armies that outnumber the force of a fictional empire (for exemple Warhammer fantasy).