Private Sub Worksheet_Activate()
Set Cible = Me.[M17]
Set Source = Feuil1.[D52]
If Cible.Value <> Source.Value And [Proposé] = "N" Then
rép = MsgBox("Valeur modifiée" & vbCrLf & Chr(9) & _
"ancienne = """ & Cible.Value & """" & vbCrLf & Chr(9) & _
"nouvelle = """ & Source.Value & """" & vbCrLf & _
"Appliquer le changement ?", vbYesNo)
If rép = vbYes Then
Cible.Value = Source.Value
Else
ThisWorkbook.Names("Proposé").RefersTo = "O"
End If
End If
End Sub