Sub Bouton3_Clic()
Dim i&, tablo, dico
With Sheets("essai")
tablo = Range("Tableau3").Value
Set dico = CreateObject("scripting.dictionary")
dico.comparemode = vbTextCompare
For i = 1 To UBound(tablo): dico(tablo(i, 2)) = "": Next i
For i = 1 To UBound(tablo)
If dico.exists(tablo(i, 1)) Then tablo(i, 1) = ""
Next i
Range("Tableau3") = tablo
End With
End Sub