With Sheets("Historique_facture")
DerL = .Range("a" & Rows.Count).End(xlUp).Row
For i = DerL To 2 Step -1
If .Cells(i, 1) = .Cells(i - 1, 1) Then
.Cells(i, 1) = Replace(.Cells(i, 1), .Cells(i - 1, 1), "-")
.Cells(i, 1).NumberFormat = ";;;"
End If
Next i
End With