À placer dans la feuille concernée (dans ton exemple : la "Feuil1" )
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Intersect(Target, Range("D5")) Is Nothing Then Exit Sub
Range("D7").ClearContents
End Sub
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Intersect(Target, Range("D5", "D7")) Is Nothing Then Exit Sub
If Target.Address = "$D$5" Then Range("D7").ClearContents
If Target.Address = "$D$7" Then Range("D5").ClearContents
End Sub