PGCE usability and validity abroad
you cannot teach with a PGCE, you need to pass the Agreg or CAPES examinations, at which point you are placed at a school. New teachers have very, very little say in where they teach. 

PGCE credits are loosely equivalent to masters credits, but my experience is that few universities will APL them in because it's effectively a professional training course. If you carry on learning at the same institution, they might have a scheme to "convert" the PGCE to an MA or MEd.