Sub Essai()
Dim c As Range
Dim Commentaire As String
Commentaire = Range("L9").Value
For Each c In ActiveSheet.Range("C4:H25")
On Error Resume Next
If c.Comment.Text = Commentaire Then
If Err <> 0 Then
Err.Clear
GoTo suite
End If
c.Interior.ColorIndex = 25 'à adapter
End If
suite:
Next c
End Sub