Sub InsertionLignes()
Application.ScreenUpdating = False
Dim DL%, L%
DL = Range("A65500").End(xlUp).Row
For L = DL To 2 Step -1
If Cells(L, "E") = "41100000" And Cells(L + 1, "E") = "41100000" Or _
Cells(L, "E") = "41100000" And Cells(L + 1, "E") = "" Then
Rows(L).Copy
Rows(L + 1).Insert Shift:=xlDown
Cells(L + 1, "E") = "51210238"
End If
Next L
End Sub