I will take the title a bit litterally: the relation between Astérix & Obélix and gallic archaeology.

The first inspiration for Asterix & Obélix are the french courses on gallic history teached to small children. The main catch phrase was "Nos ancêtres les Gaulois"/"Our forefathers the Gauls". Their you can find those gauls with big mustaches, hairs... One of the recurring theme was the defence of Versingetorix, depicted as the first defender of the fatherland. Even if the Romans brought civilization, he fought with honour. A theme reflecting the nationalistic will of revenge against Germany. This idea can be seen at the beginning of Asterix the Gaul the first note from Gossiny to Uderzo is: "Draw the Romans as the Germans entering France (in 1940)." Of course Agecanonix/Geriatrix plays the same role as the WWI veteran. Even if some elements from the vision of the celts of the XIXth century were confirmed later, there was a lot of errors in it. The first are the Menhirs, those were way more ancient.

Here are just things I remember from researching them in the podcast. I'm barely more than a casual observer, so I couldn't tell you what's common knowledge or not, but here's what I remember from researching for the History of Germany Podcast Basically episodes 8 through 12 are what you're looking for.

Here we go:

The La Tene are hardly different from the Hallstatt or others before, it's just a gradient over time, like now we call them French. Before that it was Franks. Gauls. Celts... and then we didn't have a name for them as a whole.Because the "La Tene" never actually existed. I did my research by picking apart what the La Tene were not first. Because we have debunked more false beliefs about the La Tene than we have actual facts that we do know.

But enough of what they aren't. Here are some things to look up that might help define what they were:

• Horses and chariots. Big Time. Horses had divine significance. The Romans (Julius Caesar et al) also reported this. You find chariots and horses in archeology.
• Birds. Often a bird motif in those chariots. Divination through reading the flights of birds was super common and entrenched in later Germanic cultures (which shared common ground with the La Tene, but spoke a different language)... so extrapolate what you will, fact is no one really knows the exact significance of the birds.
• Sickles. Yup. Straight up Miraculix, except we don't know a whole lot about druids except that we do have evidence of a sickle cult. Many sickles, golden, impractical sickles, and hordes of sickles have been found, all pointing to a cult (i.e. more than mere utensils or tools). The rest of herbal lore and druidic rites are mostly lost. Most of what you hear is historic fiction when it comes to druids. Very little is actually known. Caesar et all write that they did not worship in temples. Druids basically had political power. They worshiped in natural places like a grove, waterfall, cliff, meadow, some natural feature rather than a man made one.
• Let's see... They were skilled metal craftsmen. In certain goldsmithing techniques - better than the Romans (until the Romans picked it up). Also their pottery was good enough to have demand in the mediterranean areas and even be imitated and influence local, Roman, pottery. Though this happened very late in the La Tene culture... if you couldn't already call them Gauls by then.
• Other than that if you look up "Urnfield culture" Hallstatt" Uneticke Culture" ...and a few more I can't think of off the top of my head, you're basically talking about the ancestors of the La Tene, from France to Slovakia (and into the Ukraine) you have commonalities and they must have either been related, or traded. They're often all lumped in with "Celtic" ...so that's basically what I'm talking about. (but "celtic" only makes sense when talking about language families, less about genetics and peoples - a common mistake. But it seems you already know that)

I think that's all I got... unless the fact that plenty of French words have a celtic etymology that is either La Tene or older (whereas most of French comes from Latin). I find that interesting, but I'm no linguist, and my French isn't good enough to fake being one ;) So someone else would have to fill you in there.