Private Sub Worksheet_Change(ByVal Target As Range)
Dim res As String
With ThisWorkbook.Worksheets('planning')
Select Case Range('B1').Value
Case Is = ''
res = MsgBox('Voulez vous lancer la macro ZZé', vbYesNo)
If res = vbYes Then
' Appeler la macro
Else
End If
Case Else: End
End Select
End With
End Sub