Bonjour
En plus de la solution de Gibson94 je te propose cette procedure:
Option Explicit
Sub test()
Dim Bcle%
For Bcle = 21 To 1000 Step 20
If Cells(Bcle, 4) = Cells(Bcle + 20, 4) Then
Range(Cells(Bcle, 4), Cells(Bcle + 19, 4)).Insert Shift:=xlDown...