Yes, credits are transferable, within the European education system, from one program to another, through educational agreements. 

For Canadian students going to study in France, there are three possibilities:

-within an exchange program, credits can be transferred.

-within a structured mobility program, the student who is in the double diploma program does not need to transfer credits.

-within an individual mobility program, bilateral agreements on this issue may already exist between the universities or an agreement exists and the transfer of credits poses difficulties.

 For Canadian students coming back to Canada. The CICIC website (Canadian Information Centre for International Credentials)  provides very useful information on the evaluation of foreign diplomas and Prior Learning Assessment and Recognition (PLAR). Diploma assessment services compare studies done in France to studies offered in Canadian education systems.