The name of the recipient should be available for the following messages to translate them to French:
notification-mention
notification-header-mention
notification-mention-nosection
notification-header-mention-nosection
notification-mention-email-subject
notification-mention-email-batch-body
For instance, someone tried to set notification-header-mention to:
"{{GENDER:$2|$1}} vous a mentionné{{GENDER:||e|(e)}} sur la page de discussion de $3 en « $4 »."
but {{GENDER:}} is not supported (it always returns the neutral version).