First this is the video, who can help to be more understandable :
On the video, you can see the high poly model and the low poly, the two of them are in FBX format. In substance painter, the mesh is baked and it is like nothing happened.
I have only applied smoothings groups on the low and high poly (same groups), chamfer and turbosmooth only on high poly mesh. We can see volume differencies between low and high poly, is it the problem ? I don't understand because I have this problem with all my meshes and I think apply all the Tim's tips.
PS : This is a fast mesh, because I have this problem with all others.
The 3DS Max file https://mega.nz/#!P1Y1SALZ!LpPv76I9a3Tz ... _ec9oV6q1A
Thank you so much
EDIT : I thought that don't unwrap the mesh wouldn't make some problem but I think it was a bad idea. So I unwrapped it, I tried to make something clean and I baked it again (with the same meshes, only the low poly is unwrapped)
I have a new video :