Sub dudule()
Dim tab1 'Crée une variable
Set tab1 = CreateObject("Scripting.Dictionary")
' lecture colonne 1
l = 2
While Cells(l, 1) <> ""
cle = Cells(l, 1)
If tab1.exists(cle) = False Then tab1(cle) = 1
l = l + 1
Wend
' lecture colonne 2
l = 2
While Cells(l, 2) <> ""
cle = Cells(l, 2)
If tab1.exists(cle) = True Then tab1(cle) = tab1(cle) + 1
l = l + 1
Wend
'ecriture du résultats
l = 1: c = 4
For Each cle In tab1
If tab1(cle) = 2 Then
l = l + 1
Cells(l, c) = cle
End If
Next
End Sub