Private Sub VerifierDoublons_Click()
Dim tablo(), ub As Integer, i As Integer, txt As String, j As Integer, List As String
ReDim tablo(1 To Range("B65536").End(xlUp).Row) 'tableau auxiliaire pour le repérage
ub = UBound(tablo)
For i = 2 To ub
If tablo(i) = "" And Application.CountIf(Range("B:B"), Cells(i, 2)) > 1 Then
txt = "Doublon ligne "
For j = i To ub
If Cells(i, 2) = Cells(j, 2) Then
txt = txt & IIf(txt = "Doublon ligne ", "", ", ") & j
tablo(j) = "x" 'pour le repérage
End If
Next
List = List & txt & Chr(13)
End If
Next
MsgBox List 'boîte de dialogue listant tous les doublons présents dans la feuille 1
End Sub