Sub sauve()
Dim ws As Worksheet, wb As Workbook
Dim sClient$, sFacture$
Set ws = Sheets("Facture")
With ws
sClient = .Range("E6")
sFacture = .Range("B5")
Set wb = Workbooks.Open("X:\...\janvier.xls") 'à adapter
.Copy after:=wb.Sheets(wb.Sheets.Count)
ActiveSheet.Name = sClient & "_" & sFacture
wb.Close True
End With
End Sub