Private Sub CommandButton1_Click()
Dim c As Range
Dim MaPlage As Range
Set MaPlage = [A1:M40] 'A MODIFIER
For Each c In MaPlage
If c.FormatConditions.Count <> 0 Then
If c.Offset(0, -1) = "" Then
c = 0
c.Interior.ColorIndex = 6
End If
End If
Next c
End Sub