Sub worksheet_Change(ByVal Target As Range)
If Not Application.Intersect(Target,Range("C3:C34,F3:F34,I3:I34,L3:L34,O3:O34,R3:R34,U3:U34,X3:X34,AA3:AA34,AD3:AD34,AG3:AG34,AJ3:AJ34")) Is Nothing Then
select case target.offset(0,-1) 'selon le contenu de la cellule à gauche
case 1 'si ca contient 1
NumCouleur=5
case 2 'si ca contient2
Numcouleur=3
end select
Range(Target.Address).Interior.ColorIndex = Numcouleur
End If
End Sub