As the error clearly states, your view is expecting the model to be
IEnumerable<PS_Details_facture_Liste_Result>
(a sequence of items) but you are passing in a single item instead.
Either fix your view to match the model passed in by your controller, or fix your controller to pass in the model required by the view.
For example:
public ActionResult Index(int? ref_facture)
{
var model = db.PS_Details_facture_Liste(ref_facture).ToList();
return View(model);
}