Sub Boucle()
For i = 1 To 4
Cell_1 = Choose(i, "R24", "R43", "R45", "R48")
Cell_2 = Choose(i, "L24", "L43", "L45", "L48")
If Range(Cell_1).Value <> "" And Intersect(ActiveCell, Range(Cell_2)) Is Nothing Then
'Partie à traiter
ElseIf Range(Cell_1).Value = "" Then
Range(Cell_2).Select:
MsgBox "Renseignez le défaut dans votre commentaire"
End If
Next i
End Sub