RIO number: the Council of State orders effective identification of law enforcement officers
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On 29 April 2026, the Council of State, France’s highest administrative court, gave the Interior Ministry until 31 December 2026 to ensure that police officers and gendarmes actually wear their individual identification number (RIO). It is the second such injunction in three years: the obligation has existed in law since 2014, but remains largely unenforced on the ground.
Police officers at a protest in Paris in 2024. Photo: Index.
The issue is a long-standing one. Since 2014, a regulation has required every police officer and gendarme to visibly wear their RIO number – a seven-digit identifier used to trace an officer in the event of a complaint. Yet the obligation remains very unevenly observed, including in public order policing operations, where identification matters most.
Asked to rule for the first time by ACAT-France, the Ligue des droits de l’Homme and several other organisations, the Council of State had already ordered the State, in October 2023, to take the measures needed to ensure the RIO is actually worn and legible. Since too little had changed, the same organisations went back to the administrative court to have that ruling enforced. The ruling of 29 April 2026 sets a new deadline of 31 December 2026 and approves the technical specifications of the new RIO: a format enlarged to 6 cm by 17 mm – compared with 4.5 cm by 12 mm until now for police officers, an 88% increase in surface area, and a 70% increase for gendarmes – in white characters on a black background, with a bolder typeface.
The Council of State also requires the Interior Ministry to incorporate this obligation into officers’ initial and continuing training, and to treat non-compliance as a breach of professional ethics. Particular attention goes to intervention units, whose kit – balaclavas, helmets – makes officers harder to identify by sight.
This ruling goes to the heart of investigative work on police violence. Identifying the officers involved is a key step: without it, it becomes difficult to trace a chain of responsibility, to name those responsible for any misconduct, and, more broadly, to make internal and judicial oversight mechanisms work. Where the RIO is systematically not worn, it is a real obstacle to police transparency and accountability.
In its ruling, the Council of State points out that the Interior Ministry now has a firm deadline to comply. It remains to be seen whether, this time, the obligation will actually be enforced and applied across the board on the ground.