Hello Markkal,
As you clearly have some experience of dealing with the French and Italian authorities, I wonder if you could help with another enquiry on the same subject.
A few years ago I did my seaplane rating at the AeroClub di Como. I had the rating applied to my UK CAA PPL - the CAA had no problem accepting an Italian rating. I now have a French CPL, and I would like to renew the seaplane rating and get it transferred to my French CPL. What do you reckon the chances are of the French DGAC accepting this? Pretty small I would imagine - I expect they will only accept seaplane ratings done in France.