Private detective for legal professionals

Law is argued on facts. When a case stalls on a missing piece, a real address, concealed assets, an untraceable debtor, a situation to establish, our CNAPS-licensed agency investigates and delivers a report that can be filed as is before the competent court, under professional secrecy.

Written by Guillaume Pouillier, CNAPS-licensed private detective, licence no. AGD 095-2024-03-06-20190240581 · Last updated: July 14, 2026

What does a private detective do for a lawyer, a notary or an enforcement officer?

We document the facts your case requires: situation reports (adultery, cohabitation, concealed activity, breach of contract), locating debtors, defendants, witnesses or heirs, identifying assets before trial or enforcement, and the factual groundwork for measures under article 145 of the French Code of Civil Procedure.

For commercial litigation, our business investigations (unfair competition, sick-leave fraud, counterfeiting) are also conducted under counsel’s instruction; for family files, see our services for individuals, frequently prescribed by law firms. If the assignment you have in mind does not fit any of these categories, describe the fact you need established: in most cases there is a lawful way to document it, and we will tell you plainly when there is not.

Are your reports admissible, and how do you secure the proceedings?

Our reports have been accepted as evidence since the Court of Cassation ruling of 7 November 1962, under conditions we build in from the engagement letter: fair collection, proportionality to the aim pursued, respect for privacy and traceable findings. Every investigation is designed for the hearing.

Three safeguards structure our work: the agency’s CNAPS licence and each investigator’s professional card (art. L621-1 of the Internal Security Code); articles 9 and 145 of the Code of Civil Procedure, governing fairness of evidence and pre-trial measures respectively; and professional secrecy under article 226-13 of the Criminal Code, which covers our exchanges. Under counsel’s instruction, correspondence additionally passes through your own professional privilege.

Personal data collected in the course of an investigation is processed in accordance with the GDPR: collection limited to what the mandate requires, secure storage, no transfer to third parties other than the instructing party, and deletion at the end of the statutory retention period. This matters procedurally: evidence gathered in breach of data-protection rules invites a challenge; ours is built not to.

How do we work under counsel’s instruction?

You instruct us directly or on your client’s behalf: the written engagement sets the object, scope, budget and timetable. We report at your pace, progress points at the procedurally useful moments, and the final report is calibrated to be filed as is.

1. Qualifying the need. You outline the case; we answer within 24 business hours: what can be established, how, in what timeframe, at what cost.

2. Written engagement. Object, legal basis, scope and budget, in the firm’s name or the client’s, according to your procedural choice.

3. Investigation. Field work, open sources, dated findings; a progress point as soon as a result affects your litigation strategy.

4. Hearing-ready report. Chronology, findings, time-stamped photographs, sources: filed as is, it withstands adversarial debate.

We know the constraints of French procedure: case-management deadlines, hearing calendars, adversarial requirements. Our methods are documented and defensible. We regularly work with foreign law firms whose cases have a French connection; consultations can be held in English.

How much does an investigation cost for a law firm?

Our rates are public: €85 (excl. VAT) per hour, a full day (10 h) at €850, volume discounts (€80 beyond 20 h, €75 beyond 30 h, €70 beyond 40 h), administrative investigations from €350. Free written quote within 24 hours, no unapproved overrun.

Assignments for firms are often shorter than classic field cases: a debtor trace or a solvency check is handled in a few targeted documentary sessions. Investigation fees may, at the court’s discretion, be included in costs claimed under article 700 of the Code of Civil Procedure, a practice your firm will know. Full grid: our rates.

Why do Paris firms work with Prometheus?

Because we speak their language: more than 550 investigations a year, the Prometheus Group’s 30 years of experience, an agency at 10 rue de la Paix (Paris 2nd) minutes from the courts, and reports designed from the first hour for the hearing, not surveillance logs that need rewriting.

Our regular counterparts are family-law, employment and commercial-litigation lawyers, notaries facing incomplete estates, and enforcement officers lacking an address to serve or enforce. All share the same requirement: a fact established, dated, sourced and fairly obtained. That is exactly what we deliver, and when the fact you need cannot be established legally, we say so before the engagement, not after.

We operate throughout Paris and Île-de-France, notably around the Paris courts and in Hauts-de-Seine, Seine-Saint-Denis and Val-de-Marne.

Three recent examples, anonymised. For an employment-law firm, we documented within ten days the actual competing activity of a former executive who was officially “job-hunting”, the labour-court case was won on our findings. For a notarial practice, locating two heirs living abroad unblocked an estate that had been stalled for three years. For an enforcement officer, the real address and employer of an “insolvent” debtor enabled a wage attachment that cleared the debt in full.

✓ CNAPS licensed · Professional secrecy (art. 226-13) · Reply within 24 business hours

Questions law firms ask us