What is a European Doctorate Programme? I am currently a PhD student in a EU country and recently I was advised to pursue a European Doctorate Programme.

I thought that, being "European", it was some kind of regulated, inter-country program with specific rules, but I cannot find any "official" documentation from any European institution. The only things I can find by searching on google are doctorate programs from various universities that claim to be "European".

I am aware that some EU students are encouraged to do 3-6 months of their PhD (or more) abroad, but I don't know if by doing this their PhD qualifies to be a European Doctorate.

So, what is a European Doctorate Program? Is there any regulation for it by a European institution? How does it relate with doctorate programs where students decide to spend some months abroad?
I am curious to understand if there is a tangible difference between a national degree (of an EU country) and the European degree. 

As for the rules for qualifying for the European degree, I found these rules to apply:


The doctorate must, in part, have been prepared during a research internship period of at least three months in another European country.
Oral thesis presentation authorisation is granted on the basis of reports submitted by at least three professors comprising at least two from higher education institutions from two European countries other than the country in which the oral thesis presentation is to be held. The host laboratory representative cannot submit this report.
At least one member of the jury should belong to a European higher education institution from a different country to that in which the oral thesis presentation is held.
Part of the oral thesis presentation should be conducted in an official language of the European Community which is not the language of the country in which the presentation is held.


Edit (because I still cannot leave comments): 


Some universities might require a 4 month stay abroad for acquiring this title.
As for the difference in the value between the two degrees, there seems to be none. The European Doctorate seems to be a label added to the normal doctoral degree of an EU academic institution as a proof that the abovementioned requirements are accomplished. This seems to be a way to promote cooperation among EU universities from different countries, PhD student mobility and the writing of the dissertations in English, as in many EU countries they can still be written in the official language of the country.