Entrepreneur · Platform publisher · Ethical hacker
Julien Larzillière
SAINGHIN-EN-WEPPES · HAUTS-DE-FRANCE → GENEVA
( 01 ) — The person
Born in 1984. Building companies since July 2009. CEO of a group since May 2017. Publisher of sixteen platforms since 2025.
Julien Larzillière runs Groupe Tercium from 486 rue Sadi Carnot, in Sainghin-en-Weppes, near Lille. Two holdings — Tercium and Larzillière Participations — carry twelve active companies. The work has changed shape. The aim has not: understand a need, make it useful, keep it alive.
The thread runs from sales and graphic design to the web agency Apresta, five years of teaching, ethical hacking, and then ReInvent: when a task keeps repeating, it becomes a product. Two compasses: people, and ecology. The motto: nothing staged.
He describes himself as gifted and ADHD. A branching mind — hyperfocus, ideas in bursts — organised rather than flattened. That is how ten projects move at once.
September 2026
Outside France: Bcyclet, a bike shop and travel studio in Geneva since 2013; a partnership with Infomaniak since 2011 (900+ products managed, Swiss hosting); API work for the LMS Dokeos since 2022. InfoFlux, the sovereign CRM, keeps a Geneva fiduciary’s data in Switzerland.
( 02 ) — The atlas
A repeated need becomes a platform.
ReInvent, founded in the summer of 2026 and chaired by Tercium, publishes most of these tools. They are products, not subsidiaries. InfoSwitch is also a company. Facilta and Lyvre have their own, earlier stories.
A local paper and neighbour network for 25 towns between Lille and La Bassée. Free for residents, no ads in the feed, no resale of data. 695 members in September 2026.
Local dating built on anonymity. Talk first. Meet later. Name, town, photo and number are revealed in steps, only when both people have shared.
Immersive reading: sound, motion, backgrounds, narrative choices, and an editor for authors. Co-founded with Olivier Blanchon and Guillaume Reynaert. Ulule campaign, 2025.
Hiring by affinity — values and culture — before the CV. With Laurent Legrain and Guillaume Reynaert.
A move to Infomaniak: mail and history, calendars, contacts, files, servers, devices, training, 30 days of support. A deliberate alternative to Microsoft 365 and Google Workspace.
A sovereign CRM tied to Infomaniak. Contacts, pipeline, signed quotes, agenda. Data stays in Switzerland. From €9 excl. tax per user / month.
Website health: errors, suspicious redirects, spam injections, a score, alerts, a WordPress plugin. The ethical hacker’s eye, made daily.
Amicable debt collection in five steps, from a reminder to pre-litigation. A portal for the debtor. The first case is free.
Websites for craftspeople and shopkeepers. No-code, trade templates, shop, bookings, quotes. €19.90 incl. tax / month, domain and hosting included, no commission.
Lead detection for digital trades. Public data, a written angle of approach. 1.4 million companies tracked in Hauts-de-France. From €29 / month.
A network of verified CRM experts, and a comparison of more than 1,788 CRM products.
Software for law firms: matters, billing, client-account rules, data rooms, monitoring, an assistant.
A visual income allocator. Blocks, flows, a 60-month projection. No spreadsheet, no bank connection.
Automated SEO and SEA reporting — Google Ads, Search Console — as white-label dashboards for agencies.
A French press-release platform. Free publishing, search visibility.
Administrative delegation, turned into a marketplace and extended with AI. Born in 2020, still running.
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