Private Sub Worksheet_Change(ByVal R As Range)
If R.Column = 3 Then
If Application.CountIf(Range("C:C"), R) > 1 And Application.CountIf(Range("F:F"), Cells(R.Row, "F")) > 1 Then
MsgBox "Doublons!", vbCritical, "ERREUR!"
R.Offset(, 1) = Format(Now, "dd-mm-yyyy | hh:mm:ss")
R.ClearContents
End If
End If
End Sub