Private Sub ListBox1_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
Dim col As Byte
Dim li As Integer
With Sheets("Feuil1")
col = .Rows(1).Find(CDate(Me.contr3.Value), , xlFormulas, xlWhole).Column
li = .Columns(1).Find(Me.ListBox1.Value, , xlValues, xlWhole).Row
.Cells(li, col).Value = "N"
End With
End Sub