If you have worked in more than one country having signed a social security agreement with France, no single global calculation will be carried out. Instead, your pension is calculated according to each agreement.
The calculation of you pension will be carried out from agreement to agreement. This is also the case if you have worked both within the European Union and in one of the other agreement countries.
The most advantageous pension is the one that you will be given.
The country that will not be concerned by the calculation can, however, pay the pension of its own charge in accordance with national legal regulations.