They are being treated equally. A citizen of France who is resident in Luxembourg would be able to purchase. A citizen of Luxembourg who is resident in France, wouldn't.

You can have rules that apply only to residents, but they have to be applied to any resident.

Maybe I'm missing something, but Germany's personal car toll system was supposed to be offset by a rebate on car taxes that would benefit any resident (or more precisely: anybody paying their car taxes in Germany) and was found to be in violation of EU regulations. Are there special cases for tax rebates or what would have been the difference?

It is my understanding that this ability to discriminate only applies to acts by the state but not to commerce.

Perhaps this could be workable by issuing all residents a license to buy? Restriction in buying items certainly exist: guns, alcohol, etc

Presumably all residents, including those from other EU/EEA countries, would be allowed to buy. I believe discrimination against nonresidents is allowed under EU law in many contexts, for example for social benefits. (But not allowed in other contexts, for example discrimination against nonresidents can restrict the free movement of capital.)

We'll see soon enough.. we just need someone to get arrested first.

It's a good thing they picked Luxembourg for this experiment, it will cut back on the travel time for everyone involved getting to the ECJ

Even different cities have different laws, the EU is not some magical homogeneous government as much as the haters want to purport it as such.

No problem with making rules based on residency; everyone does it (vast amounts of tax law, for instance). The citizenship of the residents is irrelevant here.

>A genuine question, Aren't all EU citizens supposed to be treated equally across the EU?

Nope. At least by now, but little by little they are taking the sovereignty of members.