What is a European Doctorate Programme?

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:

1. The doctorate must, in part, have been prepared during a research internship period of at least three months in another European country.
2. 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.
3. 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.
4. 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.

I cannot cite any official documentation either, but I have a few recollections from our PhD program committee meetings. Take them with a grain of salt because I've never been involved in the European Doctorate Program bureaucracy, and we no longer adhere to it, probably for the reasons given in the last paragraph.

The European Doctorate Program is essentially a label that certifies that during the PhD years you did essentially two things (I'm not aware of other requirements):

1. You have written the PhD dissertation in English.
2. You have spent some time abroad, not necessarily in Europe (in our program the minimum period was of 6 months, but I don't know if it is a universal rule).

As far as I know, this program was born in a time (probably around 15-20 years ago) where many people around Europe, even in STEM fields, still wrote their PhD dissertation in the local language (I'm one of them) and wasn't used to visit foreign laboratories for a significant amount of time. Nowadays, many European PhD programs already require students to write their dissertations in English, some require anyway the students to spend some time abroad (or the advisors strongly encourage this), and the European Doctorate Program somehow lost its main purpose of fostering the internationalization of the PhD programs.