Assystem GmbH originated from the merger of two successful companies (Assystem Aerospace Germany and Atena Engineering) on on 1 April 2011. From this merger one of the largest engineering service providers in the German aerospace and turbo machines market was formed; delivering to the market broad technical knowledge and excellent performance, with engineering solutions that meet the high standards of quality and quantity.

The former Assystem Aerospace Germany was founded in 1997 under the name SKI-Team, as an engineering service provider in the field of aviation. The company operated primarily as a development and consulting expert servicing the areas of cabin interiors, system integration, structural and industrial services. The company became very well respected in industry; particularly in the aerospace industry. The company became part of Assystem in 2004.

Atena Engineering was active mainly in the sectors of turbo machines, automotive, and plant engineering, as a strong development partner for global companies. The company was founded in 1998 as a joint venture by MTU Aero Engines and Brunel Int. and from 2002 became a 100% subsidiary of MTU Aero Engines. In May 2005 Atena Engineering was acquired by Assystem. In 2008 the electronic area of Atena Engineering was split away and integrated into the joint venture; Silver Atena Electronic Systems Engineering.

The newest subsidiary Berner & Mattner Systemtechnik GmbH was acquired in February 2011. With this, Assystem is present in Germany with the Assystem Deutschland Holding GmbH and its three operating companies Assystem GmbH, Berner & Mattner and SILVER ATENA.