CeCILL and Free Software

Today Free Software is important in the scientific community as well as in administrations and in the entreprise. Nevertheless, the use of licenses created in the US, such as the GNU General Public License raises some legal issues. These issues may lead to uncertainties that may prevent some companies and organisations to contribute Free Software.

To provide a better legal safety while keeping the spirit of these licenses, three French public research organisations, CEACNRS and Inria launched a projet to write Free Software licenses conforming to French law.

CEA, CNRS and Inria released CeCILL in july 2004. CeCILL is the first license defining the principles of use and dissemination of Free Software in conformance with French law, following the principles of the GNU GPL. This license is meant to be used by companies, research institutions and all organisations willing to release software under a GPL-like license while ensuring a standard level of legal safety. CeCILL is also perfectly suited to international projects.

After CeCILL, CEA, CNRS and Inria released CeCILL-B and CeCILL-C, two licenses that offer other models for developpers to control the reuse of their software. They provide the same level of legal safety as CeCILL does. Authorizing the reuse of components under CeCILL-B or CeCILL-C in a software that can be distributed under any license, they thus encourage a wider diffusion of these components.

CeCILL-B follows the principle of the popular BSD license and its variants (Apache, X11 or W3C among others). In exchange for strong citation obligations (in all software incorporating a program covered by CeCILL-B and also through a Web site), the author authorizes the reuse of its software without any other constraints.

CeCILL-C is well suited to libraries and more generally software components. Anyone distributing an application which includes components under the CeCILL-C license must mention this fact and make any changes to the source code of these components available to the community under CECILL-C while being free to choose the licence of its application.

CeCILL, CeCILL-B and CeCILL-C are the first coherent family of Free Software licenses. The three licenses share most of their text and their compatibilitiy is explicitely ensured. This family has been designed as a new tool, legally efficient and original, covering many needs, for developpers of Free Software as well as companies and organizations wishing to use them with better legal safety.