Groupe AC Environnement
thegentlemen listed this organization on its leak site on Oct 31, 2026.
- Listing date
- Oct 31, 2026
- Attack date
- Oct 26, 2026
Listing text
ac-environnement.com Groupe AC Environnement is a French environmental engineering company founded in 1997 in Pontarlier, delivering integrated solutions for water treatment, wastewater, waste management and bioremediation. With 160 employees across five subsidiaries including GEG, Maraîch'Hydro and Biovéa, it has completed over 120 projects in 13 countries. Its standout project is the STEP des Voraces, France's first large-scale wastewater plant featuring demethanization serving 300,000 equivalent inhabitants. The group offers 26 specialized technical solutions spanning drinking water, industrial effluent, zero liquid discharge and circular economy applications. Led by Johan Hansma, it operates across the full project lifecycle from design and construction to long-term operations and maintenance.
About the group
thegentlemen posted its first listing on Sep 9, 2025 and has listed 1,253 organizations to date.
The Gentlemen is a RaaS group that emerged in July–August 2025, rapidly claiming over 320 victims across 17+ countries by offering affiliates a 90% revenue share, deploying a Go-based locker against Windows, Linux, NAS, and BSD systems; a compromised C2 server in 2026 revealed more than 1,570 linked victims.
Learning center
What does this listing mean?
Ransomware groups move data out of the organization before encrypting systems and threaten to publish it if the ransom is not paid. This method is called double extortion.
The listing shows that the group claims to have targeted the organization. Whether the data was published is shown by the later status of the listing.
What should you do if your organization is listed on a leak site?
- Record the listing and any published sample files; do not visit the leak site from the corporate network.
- Isolate affected systems and preserve logs without deleting them.
- Determine which data left the organization; if personal data is involved, review notification obligations with your legal team.
- Make any decision about the ransom demand together with legal, management and incident response.
- Do not bring systems back online before the attacker’s entry point is closed.
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