Double subspeciality in Internal Medicine or double specialities were possible in France until the last decade.
Specialist in Internal Medicine by my internship and four-years Clinicat (Chef de Clinique des Hôpitaux, Assistant de la Faculté), the French National Council of the Order of Physicians has recognized secondarily, according to my hospital course, in addition, my competence in medical Reanimation and nephrology.
Now it is no longer possible to carry on two specialities. The recent reforms of medical studies forbid these opportunities. Students must choose a specialty but they have the possibility to study additional higher degree compatible and authorized with their initial specialty.
In Spain you can submit the MIR system and make a specialty. A once completed, if you want to do another specialty to re-submit the MIR and can do. But you can not exercise the two, just one.