Private Sub Worksheet_Change(ByVal R As Range)
If R.Address <> [I2].Address Then Exit Sub
If Not IsDate(R) Then Exit Sub
Dim dj As Byte 'dernier jour du mois
dj = DateSerial(Year(R), Month(R) + 1, 1) - DateSerial(Year(R), Month(R), 1)
Label1.Visible = Day(R) <> dj
End Sub