Private Sub Workbook_SheetChange(ByVal Sh As Object, ByVal Target As Range)
Dim C As Range
For Each C In Target
If C.Formula = "=xxx()" Then
Application.EnableEvents = False
With C
.NumberFormat = "0.0"
'--- et aussi... ---
.Interior.ColorIndex = 38
.Font.Bold = True
End With
Application.EnableEvents = True
End If
Next C
End Sub