Non-issue, I have met several French pilots of North African heritage. The only issue at the moment is the industry has just collapsed so your chances of getting any cadetship soon are probably non existent. However I would say your Tunisian heritage could be an advantage, if you did decide to self fund (when things recover) there was always work in Africa flying the ATR, especially in the countries that were previously French colonies; so in your position you would be far better off exploring regional flying opportunities in Africa than trying to pursue employment in Europe.