Benjamin : 
I used these command lines to generate my pot file (not commited) then generated the po files.
It seems there's 400 lines missing regarding your pot file...
And even after compilation and install and setting $LANG to french it was not working (with the makefile given below not your automake stuff).
I have done a french po file, but I need to update it. So the current commited file is probably as gettext should expect.


Generate the pot file :

xgettext -d tilem -s -o tilem.pot --from-code=utf-8 --keyword=_ *.c


To generate the en_US file po :

msginit -l en_US -o en.po -i tilem.pot


To generate the fr file : 

msginit -l fr_FR -o fr.po -i tilem.pot

To compile files : 

all: fr.po en.po en_US/ fr/
    msgfmt -c -v -o fr/tilem2.mo fr.po
    msgfmt -c -v -o en_US/tilem2.mo en.po

install:
    mkdir -p /usr/share/locale/en_US/LC_MESSAGES  
    cp fr/tilem2.mo /usr/share/locale/fr/LC_MESSAGES
    cp en_US/tilem2.mo /usr/share/locale/en/LC_MESSAGES


