I'm assuming you're not a native French user or at least are trying to input many French diacritics with a non-French (eg: US) keyboard.
Instead of trying to remap the whole keyboard and always forget to remap some character, you can just map the
Multi_key) "virtual" key to some unused key on your keyboard. If your OS/distribution is already correctly pre-configured with X11, you're done.
Compose to the Menu key:
setxkbmap -option compose:menu
You can now input multiple characters by starting with the
Compose key (you have to press and release it before continuing with next characters) to assemble the final character. Those few examples should be enough to grasp it, and should come naturally:
é : sometimes but not always order doesn't matter
Ç : even a native (France) French keyboard can't input this, but in these modern days it's anyway expected to have
ç be in upper case at start of sentences.
Other common or not so common symbols from anywhere?
€ : an other visually logical combination
To input a Scandinavian
å, it doesn't appear so intuitive, unless one knowns the origin of this diacritic: a long a. So...
Note again that most of the time this stays valid for any locale or keyboard (yet there can be differences depending on locale). Eg on a native (France) French keyboard, where the
` character is on the è key:
Menu E AltGr+è =>
(obviously not useful)