The problem is that the conversion for a stored constant (gentext) you need to add to your style that allows French and then in the Style you need to add the French translation of caution for the English gentext value. Then when you set the fr attribute, it will pick the gentext for the stored value.
I think Arbortext help has the process for doing this. I may have it written down so if you have an issue in finding your solution let me know and if I have it I can send it to you.