Using the solution given by [apaderno][1], I was able to import my config from another site which is an easy way to copy content types from a project to another for instance.

1) Copy UUID from another site. 
You can find it in system.site.yml or get it with

    `drush config-get "system.site" uuid`

2) Change the UUID with 

    `drush config-set "system.site" uuid [uuid]`


Of course troubles are to be expected if you try this on sites using different versions of Drupal.

If anyone think this is a bad idea, please let me know why. 

  [1]: https://drupal.stackexchange.com/users/199/apaderno