The official GeoDAE (fr) database, used in this website, lists all defibrillators declared by the owners (public or private), as imposed by law after the installation.
There is a lot of problems with this database at the moment, like the unique identifier for each defibrillator in this GeoDAE database is randomized when exported (so is completely meaningless). Also, this database misses a lot of defibrillators.

This database in its actual state can be consulted on Api-DAE.fr, where as much as possible problems have been fixed to get some useful results.

However, since most defibrillators in public places were installed by the cityhall or by the "Service Départemental d'Incendie et de Secours" (aka "SDIS"), theses public structures can be contacted to get more informations on installed defibrillators.
This page lists all defibrillators on OpenStreetMap but actually missing in GeoDAE database, including the coordinates to contact cityhalls and SDIS to help them to contribute to the GeoDAE database.

Please visit the official website (fr) for more information on defibrillators.