What is fraudulent sick leave?
Fraudulent sick leave refers to a situation where an employee obtains a medical leave of absence while engaging in an activity incompatible with their declared health condition. This fraudulent practice harms the employer, who must bear the cost of the absence (salary maintenance, work disruption, replacement) when the medical reason is questionable or misused.
Fraudulent sick leave can take several forms:
Engaging in parallel professional activity: the employee on leave works for another employer or performs independent work, even though their health condition is supposed to prevent them from doing so.
Practicing incompatible leisure activities: intensive DIY, sports, travel, or any physical activity clearly incompatible with the declared pathology (lower back pain, musculoskeletal disorders, depression).
Unjustified extension of leave: maintaining sick leave beyond what would be medically necessary, sometimes with the unwitting complicity of the treating physician.
Simulation or exaggeration of symptoms: obtaining leave by amplifying minor symptoms or feigning incapacity.
These behaviors constitute serious misconduct that can justify dismissal, provided it can be proven beyond doubt.
Signs that should alert the employer
Certain clues may arouse an employer’s suspicion without constituting proof:
- Repeated sick leaves, especially before or after long weekends
- Social media posts of photos incompatible with the declared condition
- Reports from clients or colleagues who have seen the employee active
- Leave prescribed by a complaisant doctor known for easily issuing certificates
- Leave occurring during a tense period (conflict, negative evaluation, disciplinary procedure)
Faced with these signals, the employer cannot act alone. Any personal surveillance or request for information from the doctor would constitute a violation of privacy. This is why calling upon a licensed private detective becomes essential.
The legal framework for surveillance by a private detective
A private detective can legally monitor an employee on sick leave, provided they adhere to a strict framework defined by case law and the Internal Security Code:
Time-limited surveillance: a few days of observation are usually sufficient to establish a finding. Surveillance lasting several weeks would be deemed disproportionate.
Intervention only in public places: the detective cannot enter the employee’s home, film the interior of the dwelling from outside, or use listening devices.
Respect for the principle of proportionality: surveillance must be justified by legitimate and serious doubt, not by mere suspicion or a desire for harassment.
Objective and factual observations: the detective’s report is limited to describing what is observed (movements, visible activities), without medical interpretation.
At Groupe Hyperion, we scrupulously ensure compliance with these rules during our investigations in Montpellier and throughout France. Our experience allows us to adapt the duration and intensity of surveillance to each situation, thus guaranteeing the admissibility of evidence before labor courts. To learn more about the applicable legal framework, consult our article on evidence obtained by a private detective in labor law.
Evidence admissible before labor courts
Since the jurisprudential evolution of 2023-2025, private detective reports are increasingly admitted by labor courts as evidence, provided they meet two cumulative criteria:
Indispensability: the evidence must be the only realistic means for the employer to establish the reality of the fraud. If other conclusive elements exist (testimonies, confessions, social media publications), recourse to a detective could be deemed superfluous.
Proportionality: the infringement of the employee’s privacy must remain strictly limited to what is necessary to document the facts. Excessive or intrusive surveillance will be rejected.
The investigation report produced by Groupe Hyperion systematically includes:
- Precise dates, times, and locations of each observation
- Timestamped and geolocated photographs
- Factual description of observed activities
- Compliance with confidentiality and data protection rules
These documents have enabled many employers to establish serious misconduct and obtain termination of the employment contract without compensation.
Concrete case: Groupe Hyperion’s TF1 report
In December 2025, our director Jeremy Fontanille presented a real investigation conducted in Montpellier on a suspicious employee on sick leave to TF1’s 1 PM News. The nationally broadcast report perfectly illustrates our method: discreet observation, patience, factual findings, and absolute respect for the legal framework.
The evidence collected allowed the employer to demonstrate that the employee was engaged in parallel professional activity during their leave, thus justifying dismissal for serious misconduct validated by the labor courts.
Discover the full report and behind-the-scenes of this investigation.
How to react to suspicious sick leave?
If you suspect fraudulent sick leave in your company, here’s the procedure to follow:
- Gather initial clues: previous leaves, context of the leave, potential reports.
- Consult your lawyer or HR advisor: verify that your doubt is founded and that recourse to a detective is proportionate.
- Contact Groupe Hyperion: we will assess with you the relevance of surveillance and define an appropriate intervention framework.
- Receive an actionable report: a structured document, admissible before labor courts, accompanied by all supporting evidence.
- Initiate the appropriate procedure: dismissal for serious misconduct, recovery of paid indemnities, or even filing a complaint for fraud in the most serious cases.
Our employee surveillance services are designed to respond quickly and efficiently to these situations, while preserving your company’s peace of mind.
Groupe Hyperion operates in Montpellier, Nîmes, throughout Hérault, and across France to support employers facing suspicious sick leave. Our experience and in-depth knowledge of case law guarantee investigations conducted according to the rules and evidence that will withstand judicial scrutiny.