Sub traitement_des_données()
Dim F As Worksheet, LMax&, TCE(), TCY(), L&, D As New Dictionary
Set F = Sheets("BD")
LMax = F.Cells(Rows.Count, 1).End(xlUp).Row - 1
TCE = F.[E2].Resize(LMax).Value
TCY = F.[Y2].Resize(LMax).Value
For L = 1 To UBound(TCY)
D(TCY(L, 1)) = D(TCY(L, 1)) - (Left$(TCE(L, 1), 1) = "6" Or Left$(TCE(L, 1), 1) = "7")
Next L
For L = 1 To UBound(TCY)
If D(TCY(L, 1)) > 1 Then TCY(L, 1) = "Doublon" Else TCY(L, 1) = Empty
Next L
F.[Z2].Resize(LMax).Value = TCY
End Sub