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Work here

The Agency
7 Place de l'Europe
14200 Hérouville Saint-Clair



The Dôme
Esplanade Stéphane Hessel
14000 Caen


Here as well

Paris team
Commercial Manager
Technical Manager


Casus Belli
A marketing consultancy agency at the service of communication that, with its planners and creatives, assists companies and institutions in a changing world.

Casus Belli
An agency that reinvents the model through the exploration of social and technological innovations, in order to legitimize the actions by offering experience centered on users.


The Web


The new media


Users' experience


The model through exploration


The Changer d’angle

the manifesto

Team Team




    Jerome is an enthusiast who spent some time between the world of video games and startups before creating, with Matthieu Forget, Casus Belli; A name that is a tribute to their first love, role playing.
    Jerome, with his pioneering spirit, manages the project teams and conceptualizes inordinate operations. A finder of improbable phrases, he phones while walking (or walks while phoning) and is also a serious cook.
  • Matthieu FORGET

    Matthieu FORGET


    Matthieu could have chosen accountancy but curiously he preferred the internet when it was still in its infancy. After having created his first major business at a time when it was still referred to as a web agency, he teamed up with Jérôme to create Casus Belli. His pragmatic mind is always on alert; passionate about Strategy and a History buff, no one dares challenge business plans, profitability ratios or any subject in the form of an Excel table.
  • Corinne MARCEAU

    Corinne MARCEAU


    Corinne is pure Parisian, 100% communications agency with the names made from the initials of the founders. Corinne met Jerome and Matthieu for a single project site redesign; their freedom for innovation, research excellence, their creative sensibility, and she was seduced. After several years of traveling back and forth to Caen, Corinne has chosen to live in Normandy to think of new uses, create brand platforms and conceive communication strategies (and travel back and forth to Paris more often..).
  • Matthieu LE SOLLIEC

    Matthieu LE SOLLIEC


    Matthieu is an explorer, he lived in Liverpool to obtain a Masters in Digital Art, studied synesthesia, moved to Paris to work as AD on prestigious accounts of large agencies: Peugeot, Boucheron, Mappy, Leroy Merlin. In 2012, he pushed open the door of the agency where he can be free, sassy and an outside of the box creative realist.
  • Sébastien FINOT

    Sébastien FINOT


    Sebastien is passionate about computers in all forms but especially video games ... (him too). Self-taught, an explorer, he has worn different hats, from developer to project manager and moved in the worlds of cinema, communication, fashion, Parisian agencies (him too). After having experienced journalism, one of his childhood dreams, he returned to the root of his passion : computing. In 2012, an interview and he becomes Technical Director at the agency where he is THE expert, provides R & D and is the best provider of pragmatic solutions.
  • Morgane NEELZ

    Morgane NEELZ

    Senior Project manager

    As her cat, Morgane has lived several lives, with a diploma from CELSA in her pocket, she travelled the world as a « comm-trotter ».
    Her life at Casus Belli drives her as fast as her motorbike: it’s always with a smile that she steers between client support, reflection, coordination and project management.


    Project Manager Assistant

    Yaelle joined the agency as a project management trainee, and 6 months later, with a degree in hand, she is doing a work-study programme as part of her Master’s in Culture and Digital Communication at Paris 8. Her 10 years of basketball in competition give her a clear advantage in project coordination.
  • Quentin DUVAL

    Quentin DUVAL


    Quentin wears many caps and always with panache. Project manager, web developer and integrator, multimedia developer, the master of XHTML, HTML5, CSS3, SASS, responsive & adaptive. Quentin with his computer degree, Software and Multimedia Developer joined the agency in 2013, to challenge the limits of platforms and make them retreat, such as Drupal, Joomla. Of course, video games are part of his world !
  • Matthieu BART

    Matthieu BART


    Matthieu has been a web developer for a long time; a good ten years and joined Casus Belli in January 2022. Front and Back expert, he is also a teacher at the University of Caen. There he obtained a DUT in computer science, a Licence ATC Webmaster - specialized in web development and a Master specialized in Digital document in network & internet engineering.
  • Enzo KLEIN

    Enzo KLEIN

    UI Designer Assistant

    Enzo loves images, creation, is curious and especially passionate about user experience design. As a work-study student doing a Web Design Bachelor at MydigitalSchool, he works alongside Matthieu with a single leitmotiv: to design the best user experience.