Little Bic for France
There is a UI function to get/update BICs for several countries under yourdomain.org/civicrm/bicImport?reset=1

Afaik there is no source for French BICs yet. In order to add French BIC you would need to:


find a freely available list/source of French BIC
implement fetching/parsing the list in LittleBIC 


If you cannot do 2. you may create an issue in Github once you found the list - maybe someone can implememt it for you.