Hi, I have created a module for Prestashop v1.5- v1.6 that makes customers inactive after registration so that the admin must enable them in the backend.
Also in its configuration there is an option to redirect the customers to one cms page that you may have created. Probably an informative message with instructions..
Feel free to customize.
Enjoy!!!
Note: Beware with the use of this module, since if you already have an override of the class Customer and of the AuthController, theywill be deleted.
activatecustomer.zip