I'm assuming that the concern is that while some text is in French, other text ("Create a New Incident") is not.
The problem is that there is more involved than a single htmpl form, there are other associated forms, and also java script that is all language specific.
My recommendation would be to install a completely French secondary and route the French speaking users to that. Trying to managing the customizations of two languages in one application server is going to be difficult.