This Bugzilla instance is a read-only archive of historic NetBeans bug reports. To report a bug in NetBeans please follow the project's instructions for reporting issues.
I've set enabled=False in the properties of the module (Tools > Options > IDE Configuration > System > Modules > Infrastructure > French L10N). Restarted the IDE, the translation is always here and activated.
The problem is that French L10N module is not a module, it's rather a set of files, needed to localize other modules. To disable it, you should change ide.cfg: add a string "-locale en" to manually set your locale to something other then France.