In English, the chief's name is Vitalstatistix.

As no serious answer is coming up, I feel not entirely inappropriate to share my elementary school teachings, which may explain this icon in Asterix comics.

In french schools circa 1875-1970's (at least, the program may have stood the same, but I've grown up), the elementary school program included a fairly extensive section on French history, starting with the infamous motto: "Nos ancêtres les gaulois.". Jules Michelet may have been the instigator of this curriculum. The school manuals were uniformised, and one of the most marking event of the early curriculum was a description of "L'élévation sur le pavois", which, in Merovangian times and perhaps coming from a Germanic or Roman tradition, was a way to proclaim a chief.

And so, despite the anachronism and caricatural aspect of this image, most young kids in France could likely figure the signification of this shield (which is called a "Pavois"/Pavis).

I'm by no means an historian, but I've been reading pretty much everything I could about Asterix. One history magazine I've been reading recently was comparing a lot of things from the comics to the reality in order to spot anachronisms. It appears that the chief-carrying custom is backed by historical evidence, but unfortunately it is not related to Gaulish history. It seems to stem from Frankish customs, there is much imagery showing king Clovis atop his shield.