First of all, according to the ITU regulations there is no Amateur Service allocation around 500kHz.  Some administrations have issued permits to radio amateurs (and others) with various conditions. 

Some of these permits do not permit two-way communication.  I understand that the German authorities have issued such permits. As the possibility of an amateur service allocation around 500 is likely to be raised at the next World Radio Conference, it is unlikely that the Germans will at this point go any further than they already have.

I have no doubt (although I do not know) that the question of such an allocation has been raised with the French authorities, but for the same reason as for Germany I would not expect any developments until the next WRC proceedings have been ratified.

If we were to have a single radio prefix for all of the EU (by the way, the USA has several prefixes) there would need to be a central issuing authority, and frequency allocations across the EU would have to be harmonised. At present they are a long way from that.  For example, 6 m in France has quite severe restrictions on power level and location, and we do not have all the microwave allocations some other countries do.

John F5VLF