ok thanks a lot for the tips guys, all of that really will help me a lot!
How to refute this one? 2. Qe2 French

Morozevich had a very neat way of playing against 2. Qe2.
Then, i wonder why Morozevitch use to play KIA in this way :
1.e4 e6 2.d3 d5 3.Qe2!?
True its not really the same structure, because u can play Philidor mode with c3-Qc2 in some variations.
Anyway Qe2 is not really trash move, it's just a move with interesting positions.
It is better to play such moves with some knowledge (need few), than going for main lines which need very much work and is not for everyone, asking some skills and is much more difficult to handle than sub lines like 2.Qe2 or 2.b3.
For instance :
Analysis from John Emms's Starting out KIA.

As French player I actually started replying this as white, facing it in a regional game last year and getting completely out of the French comfort zone.
I honestly believe that the question doesn't necessary apply so much as to how good Qe2 is (which is too early a judgment, it's not as if Black's better), more how it defers Black's most natural plan in the defense. While mentioning it, even 2....d5 3.exd5 Qxd5 4.Nc3 Qd8 is perfectly playable, but the characteristics of a closed French are gone.
This last part is in fact what happens with almost any Black reply, similar with the Exchange variation yet more unbalanced.
To actually answer the OP's question: c5 is objectively the best answer. It actually gives Black a minor plus, but the psychological part of having to defer to a Sicilian setup will diminish that advantage.
What I do truly enjoy is Black players premoving d5. Playable but not at all what they were expecting.
2. Qe2 is junk. Just play solid chess and white will be wondering why he ever played this thrash.
Advicing "just play solid chess" is like to say just win, or just do the right moves.
He is correct. Worrying about, and not knowing what to do on move 2 is rediculous. Follw opening principles, and youll be fine.