CLEARSY was founded on January 1st, 2001 by a group of engineers that had industrialized the formal modeling tool referred to as Atelier B, used in the rail transport industry to create safety software.

CLEARSY was created on the basis of two principal objectives:

  • to develop formal type methods and tools
  • to develop software and systems that justify the use of formal methods

Today, CLEARSY employs approximately 140 engineers, consultants and experts in the regions of Aix en Provence, Paris, Lyon and Strasbourg. CLEARSY engineers are skilled in various engineering fields (systems, mechanics, electronics, software, operational safety). They have IT tools and an electronic laboratory to create prototypes and conduct trials. Collaborations with laboratories and industrial partnerships ensure the production of the various system components (sensors and interfaces).

CLEARSY is proposing three services: 

1- Development of engineering tools and methods: Atelier B (B method), CLEARSY DATA SOLVER, ERTMS simulation tool, Tools for visualisation of baseline 3 braking curves, DAME (data logger, monitoring tool), development of methods and prototypes within industrial R&D and European projects, development of specific and custom industrial engineering tools.

2- Engineering systems and software development: committed to achieving results, CLEARSY designs and validates systems and software. The company proposes design, validation, commissioning and project management.

3- Engineering and technical support in the following fields: formal methods, system and software development, testing, safety, validation of software and electronic system.


CLEARSY’s originality lies in its expertise in Systems, Software and Operational Safety, as well as its mastery of formal methods.

These are used:

  • In the specification phase to validate specifications, demonstrate coherence and represent the system in the form of a digital and graphical model
  • In the realization phase for safety software to demonstrate that the software complies with its specifications and to prove that no coding error exists.

CLEARSY clients include major industries and originators, essentially in the field of rail and road transport. Current CLEARSY projects essentially involve the realization of safe systems to comply with Standards 61508, 50126, 50128 and 50129.

CLEARSY is an active member of the SCS (Secured Communicating Solutions) global competitiveness cluster dedicated to digital technologies. Created in 2005 in the Provence Alpes Côte d’Azur region, it brings together an ecosystem of nearly 300 industrial players, large groups, SMEs and startups, research laboratories and universities that work together to develop and market innovative products and services to generate growth and jobs in promising markets.
The SCS cluster has accredited the FUI LCHIP (Low Cost High Integrity Platform) project which led to the invention of the CLEARSY Safety Platform.