In Europe and beyond, several advisory bodies have been monitoring the developments in the field of Synthetic Biology. Reports have been sent to national governments for information on the developments and possible regulatory and risk assessment questions raised by this field. To put the issues in a broader perspective, four national biosafety advisory bodies (the French High Council for Biotechnology, the German Central Committee on Biological Safety, the Netherlands Commission on Genetic Modification and the Belgian Scientific Institute of Public Health (Biosafety and Biotechnology Unit)) decided to join forces and organize an international scientific workshop to review some of the latest scientific insights and look into possible challenges in the risk assessment of Synthetic Biology. The SynBio Workshop (Paris 2012) - Risk assessment challenges of Synthetic Biology took place on the 12th of December 2012 and gathered scientists from biosafety advisory bodies from fifteen European countries, from the European Food Safety Authority as well as representatives of the European Commission, together with research scientists selected for their excellence in the field. The workshop was divided into two sessions: the first session gave an overview of four major fields in Synthetic Biology. The second session was set up for discussion with a scientific panel and the audience to identify and address relevant questions for risk assessment raised by recent and future developments of Synthetic Biology. An overview of the workshop and the discussion points put forward during the day are discussed in this document.