The agency
Prometheus Détective Privé – Paris
A Paris agency at 10 rue de la Paix, backed by the Prometheus Group: CNAPS licensed, 30 years of experience, national and international network.
Who we are
Prometheus Détective Privé is the Paris branch of the Prometheus Group, located at 10 rue de la Paix (Paris 2nd), steps from place Vendôme and the Opera. Our private detectives, all licensed by the CNAPS (the French private-security regulator, Ministry of the Interior), put investigative rigour at the service of your rights, for individuals, businesses and legal professionals, in French, English and Spanish.
Our conviction is simple: evidence only has value if it is lawful and admissible. Every assignment is covered by a lawful mandate and conducted according to the profession’s code of ethics.
Who runs your investigations?
Three directors, all with investigative backgrounds. In line with our discretion policy there are no portraits: an investigator’s face is a working tool. Here, however, is everything that can be public.
Guillaume Pouillier
Founder & managing director
CNAPS-licensed private detective, he has run Groupe Prometheus since founding it in 2017 and authored the Village de la Justice article on the legal obligations of private detectives.
Specialities: direction of the firm’s investigations, evidence strategy with counsel.
CNAPS licence: AGD 095-2024-03-06-20190240581
Bruno Hallez
Associate director
Nearly 25 years of investigations, first within public investigation services. A private investigator since 2024, he joined Groupe Prometheus as an associate in 2025.
Specialities: surveillance and tailing, bug and hidden-camera sweeps (TSCM), investigator training.
CNAPS licence: [TO BE PROVIDED shortly]
Frédéric Masson
Associate director
Nearly 35 years of investigations. Trained at the Fontainebleau national judicial police academy, a private investigator since 2008 and an associate of the Group since 2021.
Specialities: surveillance and tailing, criminal defence counter-investigation, administrative inquiries.
CNAPS licence: [TO BE PROVIDED shortly]
Our licences & ethics
- Agency CNAPS licence: AUT-075-2116-12-06-20170618953: verifiable on the CNAPS online service
- Professional liability insurance: Hiscox, policy HA RCP2017129
- Detectives holding individual licences and professional cards, Guillaume Pouillier: AGD-095-2024-03-06-20190240581 · Bruno Hallez: [TO BE PROVIDED] · Frédéric Masson: [TO BE PROVIDED]
- Activity defined by article L621-1 of the French Internal Security Code
- Professional secrecy (art. 226-13 of the Criminal Code) and ethics (art. R631-9)
- Reports admissible before all courts (Court of Cassation, 7 November 1962)
- Member of the WAD, World Association of Detectives, the profession’s international network
Why don’t our detectives show their faces?
Because discretion is a working tool: a recognisable investigator is a burned investigator, on a surveillance, during a mystery visit, even in the courtroom. Our legitimacy can be verified differently: CNAPS licences checkable online, a fully registered company, publicly documented methods. To compare agencies point by point, see our guide on how to choose the best private detective in Paris.
It is a definitive choice, and a rare one to state openly: many agencies publish portraits out of commercial mimicry, at their own investigators’ expense. Keeping our investigators anonymous keeps their full operational capability on your cases. In return, everything that can be public is: the agency’s and manager’s licence numbers above, professional insurance, the full legal entity in the legal notice, our methods and our rates. Guillaume Pouillier also writes in the French legal review Village de la Justice, see his article on the legal obligations of private detectives (in French).
In the media
Our investigators regularly appear in mainstream video formats, always within professional secrecy: no real case is ever discussed. Two recent, verifiable examples below (in French).
“Detective vs cheaters”, on the Ophenya channel (in French).
“On sick leave, caught red-handed by a detective”, Real Life: Reportages & Enquêtes (in French).
Visiting the agency
10 rue de la Paix, 75002 Paris: by appointment only, to preserve the confidentiality of visits. Metro Opéra (3, 7, 8), Madeleine (8, 12, 14) or Tuileries (1); RER A Auber 5 minutes away.
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Related pages
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