The problem here is that some views (not all of them) can't access to some css&js files(not all of them) ("404 Not found" error).
For exemple View of .../Details/Index/1 can't access to 1file css and 1file js (it can access all other files), but the View of .../Recherche/result can access to all files.
This problem happens when the user is connected and when not connected.
I didn't modifie the web.config file.
All View are related to one Layout, in there I inluded the css files:
<link href="Content/file.css" media="all" rel="stylesheet" type="text/css" />
And one last thing, all css files are in 1 folder and all js files are in 1 folder.