Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Column < 3 Or Target.Column > 6 Then Exit Sub
If Not Cells(3, Target.Column) = Application.UserName Then
MsgBox "Accès non autorisé!", vbOKOnly + vbexcamation, "ERREUR UTILISATEUR"
Range("A1").Select
End If
End Sub