Who we are

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 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 a hundred 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.

Our values

Towards our staff:
ClearSy is a dynamic company, made up of a team of people with specialist talents in their own area and using state-of-the-art formal methods. We differentiate ourselves from our competitors through the excellence of our staff and the innovation shown by the company, which has succeeded in developing a strong team spirit and a significant coherence so that we can communicate and move forward together to achieve our different projects.

Towards our customers:
We make it a point of honour to satisfy our customers. Since we were founded, our ideas and activities have embodied a strong entrepreneurial spirit and a passion for technology, which enable us to identify our customers’ needs, listen to what they tell us and offer appropriate solutions. Developing our skills is one of our priorities and an axis of progress; in addition, our research activity is an area of special attention which requires permanent investment. Our ability to react immediately is the key to our success.

Clearsy est membre de...

Clearsy is a member of the “Networked European Software & Services Initiative”. NESSI aims to provide a unified view for European research in Services Architectures and Software Infrastructures that will define technologies, strategies and deployment policies fostering new, open, industrial solutions and societal applications that enhance the safety, security and well-being of citizens.

> CLEARSY is member of the Comité Richelieu
> CLEARSY is member of Foundation OpenECTS