CLEARSY

Safety software and systems designer

The CLEARSY company

CLEARSY was founded on January 1, 2001 by the team of engineers responsible for the industrialisation of the formal modelling tool called Atelier B, used in the railway sector to produce safety software.

CLEARSY: safety systems engineering

We are a French SME, specialised in the realisation of safety systems and software from level SIL1 to SIL4. We develop complex systems by ensuring their design, their validation, verification and safety study, right up to their commissioning.

CLEARSY produces safe systems and software in the railway, automotive, military, space and nuclear fields.

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Presentation

News

CLEARSY systems in Volume 5 of ‘Railway Signalling and Automation’ book

29 October 2025 | Offers

In this reference work, the chapter entitled ‘Full automation of a metro line’ refers to two CLEARSY safety systems without […]

Modernise without compromising safety: discover CLEARSY’s system analysis and renovation services

28 October 2025 | Computer science

CLEARSY presents its system analysis and renovation services, a comprehensive offering dedicated to the modernisation of safety-critical systems. Designed to […]

CLEARSY works to improve the mathematical demonstration tools of Atelier B

21 October 2025 | Computer science

As part of a project funded by the French National Research Agency (ANR), CLEARSY is collaborating with LORIA (Nancy), CRIL […]

CLEARSY-HITACHI framework agreement for new simulation solutions

14 October 2025 | ERTMS

CLEARSY and Hitachi Rail have signed a framework agreement to support the development of European rail infrastructure through high-level simulation […]

CLEARSY Safety Platform, a computer for the safe control of equipments

7 October 2025 | Component

CLEARSY Safety Platform, a computer for the safe control of equipments. In 2021, CLEARSY pass the certification of its SIL4 […]

The B WORKBOOK is now available

1 October 2025 | Computer science

The user manual for B Method, the B WORKBOOK, is now available on CLEARSY’s GitHub: (https://github.com/CLEARSY/BWORKBOOK). After several months of […]