This album sees Asterix and Obelix return to Rome to assist Chief Vitalstatistix save face after a drunken boast made at the house of his despised brother-in-law in Lutetia. Basically his brother-in-law is quite a rich merchant, who doesn't have to travel any more because he has other people to do that for him. Anyway, Impedimentia (the Chief's wife) seems to be a little upset that her brother is a well to do merchant while her husband is the chief of a village that has basically rejected the Roman way of life.
The boast involved making a soup that was seasoned with Ceaser's laurel wreath (a band of leaves that sits on Ceaser's head, though normally held over the head by a slave, and even then they were only 'worn' on ceremonial occassions). The problem is that Ceaser has the wreath and Asterix and Obelix (after Obelix, who drunkenly agrees to help Vitalstatistix fulfil the boast) have to some how get it. While one would expect them to simply charge into Ceaser's palace and bust the place up, Asterix does remind Obelix that while the potion gives them superhuman strength, it does not make them invulnerable, and since Ceaser's praetorian guard are of a much higher calibre than the legionaries camped perpetually outside their village, that course of action is not open to them.
So they do the next best thing and attempt to sell themselves as slaves, but to get into Ceaser's household they can only be sold from one particular action house, and getting to be a slave there is no easy task, and even then, they end up getting sold to the wrong person (rather than Ceaser, they are sold to a rather well to do household, but not actually Ceaser's household).
Some have suggested that huge amounts of research have gone into these albums, and also it takes us inside the home of a well-to-do Roman. I would argue against that because, even though research has been done, the writers have no qualms in bending or distorting history to suit their purposes (particularly with the jokes regarding Brutus that appear occasionally). Further, one does not need to know anything about Roman history to enjoy the Asterix albums, however if one's entire knowledge of Ancient Rome is based upon Asterix albums, then I would have to say that one's knowledge of Rome is going to be sadly deficient.
I would suggest that this is probably more poking fun at life in the capital city. While Rome is the centre of the universe in this time, at the beginning of the album we jump to Lutetia for the backstory, which is also said to be the centre of the universe. The question that is raised is how can two places be the centre of the universe when there is only one universe? I would suggest that this has a lot to with national pride. Even then, while this attitude to one's capital city may be the case in Europe, it is not necessarily the case elsewhere. For instance here in Australia Canberra (our political capital) is a city where everybody wants to spend as little time as possible, while the two major cities compete against each other for being the best (and being a Melbournian I would have to say that my opinion is going to be biased).
I can't say that I notice much of the elitist attitude of the major city here in Melbourne, probably because Melbourne is more of a culture capital rather than a financial capital. Over in Sydney you will encounter many more over-priced restaurants and ridiculously high valued properties and suburbs, as well as a much more elitist attitude among the people that live there. The problem with these places is that unless you earn a relatively high income, it is very difficult to survive in a place like that. However, the attitude of being able to purchase goods at a shop that has the title 'by appointment of her majesty' (as you will see on Collins Street here in Melbourne) is very much a psychological thing. To have bought something from a shop like that (such as Hardy's Jewellers) and the fact that you read the financial newspaper, instead of the typical rags that the Hoi Poloi read, gives one the psychological belief that one is better than the Hoi Poloi. The truth is that it is all rubbish.
However the mind set of living in such a city and being able to shop at places like that, as well has having a house in a pricey suburb and driving an expensive car, creates the belief that one has succeeded, and gives the impression to those around you that unless they do the same thing then they have not succeeded. However it is all an illusion. People who drive BMWs and live in Toorak are just as likely to suffer depression as those who live in Sunshine and drive a $500.00 Datsun Sunny (if it still actually drives). Sometimes though, those who live among the Hoi Poloi, and drink in their pubs, have much more of an identity than those who are constantly trying to prove themselves among their peers. In the end it is all a matter of identity, and in many cases an identity that you are trying to create for yourself. Sometimes, actually, most times, the quiet, humble, ascetic identity can be much healthier than trying to obtain a high valued, elitist, identity, namely because one does not have to forever maintain that identity at a price that one simply cannot afford.