Hmmm, you asked that question some time ago in the trip report forum, didn't you?
U're going to start your own low-cost carrier?
I think France is, without doubt, a great market for Tunisian airlines!
I would start to
with A321s or B738s, as I think cheap tickets from France to Tunisia will be very attractive! Don't know about the fares of TunisAir, etc though.