The logic of the system is simple: In the EU, only the state where you reside is competent for driving license issues. As a rule, other member states — including the one where you originally obtained your license — should refuse to issue a (duplicate) license. It's sometimes possible to fall through the cracks depending on the kind of evidence required to ...
Since I no longer plan to live in France, am I indeed obliged to change it into a French one?
Your plans don't matter - the member state where you currently have normal residence does:
DIRECTIVE 2006/126/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL
of 20 December 2006 on driving licences (Recast)
Issue, validity and renewal