Although private investigators are often associated with strictly private matters, their involvement within local authorities is now a well‑established legal and operational reality. However, such involvement must comply with strict formal requirements.
Local authorities —municipalities, departments, regions and inter‑municipal public bodies— face increasingly complex issues that sometimes exceed the investigative capacities of their internal services.
Grant fraud, unjustified staff absences, misappropriation of public assets, conflicts of interest or monitoring of public contracts: these are all situations in which engaging a private investigator may be not only justified but necessary. This engagement, far from being left to the sole discretion of elected officials, is governed by a legal framework that must be perfectly mastered. For investigators, these assignments take place in a demanding administrative environment where compliance with public rules and legal requirements determines the admissibility of their work.
A legal basis confirmed by case law
The intervention of private investigators is not expressly defined in legislation, but it is not prohibited either. Law No. 83‑629 of 12 July 1983, codified in Articles L.621‑1 et seq. of the French Internal Security Code, regulates the profession without distinguishing between public and private clients.
The admissibility of private investigators’ reports in administrative courts was confirmed by the French Council of State in a ruling dated 16 July 2014 (No. 355201). This decision illustrates that such intervention may be essential to justify potential infringements of fundamental freedoms, particularly privacy, when a major public interest is at stake.
Administratively, the use of a private investigator is subject to two constitutional principles: legality and proportionality. The investigation must fall strictly within the legal powers of the authority, and the mandate must be precise, time‑limited and based on legitimate suspicion.
Why do local authorities hire private investigators ?
Local authorities are subject to oversight by the Court of Audit, regional audit chambers, the prefect and their own internal audit services. Hiring a private investigator is valuable due to their independence, expertise and discretion. They can gather admissible evidence while respecting privacy rights.
The most common assignments include:
- Absenteeism control: verifying the legitimacy of sick leave.
- Undeclared secondary activities: monitoring compliance with exclusivity obligations.
- Damage or unlawful occupation of public property.
- Integrity and ethics: investigating suspected corruption or unlawful interest‑taking.
- Social benefits fraud: domicile checks, undeclared income, changes in family status.
- Economic intelligence: pre‑contractual due diligence for complex public procurement.
Public procurement: an essential step
Before any investigation, the engagement of a private investigator must comply with public procurement rules. This is not a mere administrative formality but a guarantee of transparency, regularity and legality in the use of public funds.
Depending on the amount, the engagement may take the form of an accepted quotation, a purchase order or a formal contract. Precise identification of the contracting authority, the relevant department and contractual references is essential from the outset.
Chorus Pro: mandatory for invoicing
Since 1 January 2020, all invoices addressed to public entities must be submitted through the Chorus Pro platform. A private investigator who does not master this tool cannot invoice a local authority.
At Agora Détectives, this dual expertise —operational and institutional— enables us to support public actors effectively and ensure full compliance with their requirements.
Ethical guarantees and evidentiary admissibility
Local authorities require strict compliance from their service providers. Investigators must provide all mandatory documents: company registration extract, up‑to‑date tax and social certificates, professional liability insurance and profession‑specific authorisations.
The mission’s scope, the individuals concerned, the duration and the expected types of evidence must be clearly defined. Our agency holds the authorisation issued by the National Council for Private Security Activities, ensuring the admissibility of our reports. We also ensure full compliance with GDPR requirements.
To avoid evidentiary contamination, internal administrative checks should not be mixed with external investigations, ensuring a clear chain of custody before administrative or criminal courts.
Who may mandate a private investigator within a local authority?
Authorised interlocutors may include:
- Mayor
- President of an inter‑municipal authority
- Chief executive officer (DGS)
- Human resources department
- Legal department
Engaging a private investigator marks a shift from reactive to proactive management of fraud and integrity risks. More than a service provider, the investigator becomes a valuable partner in safeguarding transparency and ethics at the heart of public action.
About Our Analyses
Founded in Paris in 2009 by Anthony Caudal, Agora Détectives assists individuals, businesses, and legal professionals with their private investigation, evidence gathering, and investigative needs, both in France and internationally.
Our articles are based on our professional investigative experience and supplemented by research, legal analysis, and monitoring conducted in collaboration with Laura Alexandra Peregrina-Gonzalez, a trained legal professional.
This interdisciplinary approach, combining private investigation practice with legal analysis, enables us to interpret current events while taking into account their practical implications regarding evidence, fraud, litigation, and investigations.
