This is PrestaShop module that will give you possibility to mark some CMS pages as a pages visible for logged users only. If someone will not be logged - it will not see the contents of the page and it will be necessary to log in to see contents.
With this module you can mark selected pages only, this means that some cms pages will be visible for everyone, and some of them only for logged customers
module is available here (screenshots, video, download)
Private CMS - pages for logged customers only