iNavX Help is default integrated in English. The French Help is only available if you have an internet connection (WiFi ou 3G). The reason is that the French help has many screenshots, which makes a file with a size incompatible, to date, with the limit imposed by Apple for the maximum size of their applications. It is, thus, only accessible through a web link.
To have French Help, when you have no network connection, you can download it in PDF file from your iPhone or iPad : I am updating systematically on iNavX page from my website, bottom page. A long press on the icon of the file will open in iBooks where it will be recorded and will be available for offline viewing.