Tryton

"Is a three-tier high-level general purpose application platform under the license GPL-3 written in Python and using PostgreSQL as database engine. It is the core base of a complete business solution providing modularity, scalability and security.
The core of Tryton (also called Tryton kernel) provides all the necessary functionalities for a complete application framework: data persistence, extensive modularity, users management (authentication, fine grained control for data access, handling of concurrent access of resources), workflow and report engines, web services and internationalisation. Thus constituting a complete application platform which can be used for any relevant purpose."