Unlawful or unfair evidence: two illustrations of the conditions for admissibility
Cass. soc., 1 April 2026, n° 24-21.452 & 24-19.193
Two recent illustrations of the conditions for admissibility of unlawful or unfair evidence in employment litigation:
A reminder of a now-settled framework: the unlawfulness or unfairness of a means of evidence does not necessarily lead to excluding it from the proceedings.
The judge must balance the right to evidence against the conflicting rights involved, the right to evidence being able to justify the production of material infringing other rights only on condition that such production is indispensable to its exercise and that the infringement is strictly proportionate to the aim pursued.
Case 1: Production of documents covered by medical confidentiality
Employees of a nursing home (EHPAD) produce excerpts of the nursing log, in breach of medical confidentiality, in order to demonstrate the reality of their duties as nursing assistants.
Admissible evidence:
the residents' names had been redacted;
the document did not indicate the name of the facility, so that it did not, in itself, allow the residents to be identified by their room number;
the room number indicated made it possible to understand that these were different patients and not several visits to the same room.
Of note: also produced were witness statements challenged by the employer, in particular that of a colleague who was also in litigation with him.
Case 2: Production of files extracted from the director's computer
During his precautionary suspension (mise à pied conservatoire), an employee obtained files on a director's computer by accessing the company's IT system. This obtaining was characterized as unfair and unlawful, as infringing the director's private life.
Admissible evidence:
obtaining these disputed documents was strictly necessary for the exercise of the employee's rights of defense in the dispute against his employer, in order to demonstrate that he had been dismissed for having testified to acts of moral harassment committed by the director against one of his colleagues, as well as the blackmail exercised by the latter to make him retract that testimony;
the infringement of the director's personal life was strictly proportionate to the aim pursued, the employee having confined himself to producing three files retrieved from the latter's computer.
A body of case law that now shapes evidentiary strategy in a structural way.
Sources: French Supreme Court, 1 April 2026, appeals n° 24-21.452 and n° 24-19.193