@admin.register(Cliente)
class ClienteAdmin(admin.ModelAdmin):
    list_display = ['ragione_sociale', 'forma_societaria', 'titolare',
        'partita_iva']
list_filter = ['forma_societaria']
search_fields = ['ragione_sociale']
inlines = [RecapitoInline, SedeInline]

def get_form(self, request, obj=None, **kwargs):
    form = super(ClienteAdmin, self).get_form(request, obj, **kwargs)
form.base_fields['prodotto'].widget.can_add_related = False
return form
Django 1.7 удаляет кнопку «Добавить» из встроенной формы