I've read about AllAtps and the students are rushed throught at a break-kneck pace....7 days/week. What they don't tell you is that a lot of students fail the written exams because they don't have the time to properly prepare. Another drawback for you, assuming you're from France, is they don't train foreign (non-American) students. Usually if it sounds too good to be true then it is too good to be true. It's a good place to buy 100 hours of multi but the 3-month wonder course is another story....and no I have not trained there. I'm in the process of trying to find a good flight school myself.
I hope this helps,
Taluft