My refurbished ThinkPad T460s shipped with an International US layout keyboard. And with the default Xenocara configuration, I couldn’t type accents. As I write 90% of my real-life emails in French, this was an issue.
Nowadays, most free software is localized. I don’t really care about using a french GUI but it sometime helps to automatically set tools like spellcheckers. Here’s the variables set I use so that most of my (graphical) applications speak french on OpenBSD (5.0):
# vi .profile LANG=fr_FR.UTF-8 MM_CHARSET=UTF-8 LC_ALL=$LANG LC_COLLATE=POSIX; export LANG MM_CHARSET LC_ALL LC_COLLATE
Voilà, c’est fait.