Private Sub Worksheet_Change(ByVal Target As Range)
Protect "toto", UserInterfaceOnly:=True
Set Target = Intersect(Target, UsedRange)
If Target Is Nothing Then Exit Sub
Application.ScreenUpdating = False
Application.EnableEvents = False 'désactive les évènements
For Each Target In Target 'si entrées multiples (copier-coller
If Target.Column > 1 And LCase(Target) = "chaise" Then Target(1, 0).Locked = True 'verrouille la cellule à gauche
Next
Application.EnableEvents = True 'réactive les évènements
End Sub