Option Explicit
Sub Copier()
Dim ThisWb As Workbook, ActWb As Workbook
Dim chemin As String, plage As Range
chemin = ThisWorkbook.Path & "\Fichiers\Destination.xls"
Set ThisWb = ThisWorkbook
Set plage = ThisWb.Sheets(1).Range("a1:n23")
Set ActWb = Workbooks.Open(chemin)
plage.Copy ActWb.Sheets(1).Range("a1")
ActWb.Close True
End Sub