By default (and in most cases), any creation is protected by law and the use of it requires permissions from its author(s).
If your intention, as a creator, is to share your work and call it a “libre objet”, it means that you want to allow any person to be able to study, copy, build, distribute and modify your design and to grant them these rights within a certain legal framework.
We believe that by doing so, you increase your chances of getting your work known, promote a certain way of creating and prevent the possible misuses of it.
For your work to be considered a Libre Objet, you must publish it under a license that enforces the basic freedoms promoted by the Free Software Foundation. To help you in this matter, here is a list of licenses that we prefer and that we encourage you to use.
http://artlibre.org/licence/lal/en
We will only accept work that is under one of these three Creative Commons licenses (any other CC license is not considered open source):
https://gnu.org/licenses/gpl.html
There is also some specific open source hardware licenses available. You might have heard of the TAPR OHL or the CERN OHL.
To assist you in choosing the right license for your work, here is some links that will help you understand the differences and particularities of each one.
All the above licenses might not give you the complete rights you need to replicate at any time anywhere the manufacturing of the objects published here. You must investigate further by yourself to get a correct and complete information concerning this point.