Worst case, you can simply delete the settings.json files located in the saves folder. It will simply reset the options you chose thus reverting back to english. However, I've tested it on my side and the files load properly. Is there any debug.txt file created in the game folder after the game hangs ?
Thanks a lot for this answer.
The debug file say:
<XML Error> Lang.xml is not formatted properly
If I compare fr.xml and other language files, I may see they are not formated the same way.
If I play in french and I close the game, I may no more lauch it.
However, If I switch the game in english before closing, I may launch it and then switch back to fr... and it works.
Hope it will help... and thanks for the good job.