If I would have to guess, I would predict that this Thursday will not be quite as bad as the initial national strike last December. The French news last night had a report on how, after a month of protest, the strikers cannot afford to miss much more work. Although many unions hope this Thursday will bring more people out (and it probably will), many are getting tired and need the money, so will show up to work. For flights, Air France tends to cancel domestic flights first and keep longer and mid-range ones going (as much as possible), I would wager that TUN flight goes. The only trouble may be if the air traffic goes on strike. If that is the case, AA should reroute you via a different airport. Bonne chance!