I'm Canadian, so my answers would probably be all wrong in France. Anyway I would say:
yum/yummy = miam (with 2 M) or mioum or menoum
gee = no equivalent
haha = ahah, ha ha, hahahha (it doesn't matter)
geez = Jezz
ew = yark or eurk or ark
meh = pff
nah = non
ugh = urgh (with an R)
jesus = oh mon dieu
rawr = Grrr