BMW, Audi and Mercedes-Benz are definitely considered luxury brands in Germany - even their entry level vehicles. Otherwise people wouldn't be paying thousands more for an Audi A3 - BMW 1-series or Mercedes-Benz A-class over same segment cars made by Ford, Opel (GM Europe), Renault, Peugeot, KIA, Hyundai, etc. I lived in Germany and surrounding countries (UK, Netherlands, Belgium, France) for almost 30 years, and these three brands are undoubtedly luxury or premium brands in Europe that people aspire to own. No one aspires to drive a KIA or Hyundai in Europe
In Germany, people aspire to buy German cars, partly out of loyalty to their own country (just like most countries and their indigenous car companies). I am not talking about the rest of Europe with regard to German cars, where it is treated more like a luxury item, similar to the US.
In Germany, there are many average citizens who buy (relatively) stripped-down MB C class cars, which are not that expensive in Germany. Ford, Opel (GM Europe), KIA, Hyundai are more economy cars in most cases, so they wouldn't be compared to a MB or BMW, or even a Lexus (Toyota), or Acura (Honda). If you were to look at the engine offerings of MB and BMW in Germany, you would usually see one or more engine options on each car that are smaller than those offered in the US. Most of the German cars marketed in the US start out with higher trim levels than those available in Germany. But obviously, an S Class or 7 Series is going to be a luxury car in any market.
In Germany for 2016, Audi, MB, and BMW had about a 9%, 9%, and 8% market share respectively, but had only about 1.2%, 2.1% and 1.9% market share in USA. VW had a 20% market share in Germany for 2016.
Renault and Peugeot are French, which is whole 'nother story in Germany (or anywhere else where quality is appreciated), so I would not expect hardly any sales of those in Germany.
Regarding your "Tiers," it is a reasonable try, but any such endeavor is doomed due to the wide variation (in price and luxury) of the various models in each line. As I said before, the MB C Class and S Class are not in the same league when it comes to price or luxury.
IMO, calling a Chrysler a luxury car of any kind is not something I could agree with.
I believe that Acura and
Infiniti (and eventually Genesis) are on par with Lexus, except maybe for the Lexus LS, which doesn't sell much anymore (only 5514 units sold in USA for 2016). The market is rapidly moving to toward SUV's and CUV's, even in the Luxury markets.