In matters of agreements as to succession
Fundamental :
The Certificate of Succession does not provide an additional means of evidence of the status of heir in the Member States, as it is not possible to draw up a certificate of succession within the framework of an internal succession; this instrument is for use only in international successions (Article 62[1]). It will produce its effects automatically if it is presented in a Member State other than the State of origin.
However, those Member States that are not bound by the Regulation and third States are not obliged to recognise it.
Example :
A certificate of succession established in Spain will be recognised automatically in France. It will not necessarily be recognised in Morocco where the deceased owned property.