Electronic monitoring (EM) or GPS tagging is a security measure which may be imposed for a two-year period which is renewable once for misdemeanours and twice for felonies, within the framework of the release of a person convicted for certain acts and sentenced to a long prison term. EM may be used in the framework of conditional release and social monitoring (prison sentences of at least 7 years) or judicial surveillance (prison sentences of at least 10 years).
Electronic tags, generally worn on the ankle, are completed by GPS boxes. This system, managed by the penitentiary administration, tracks the location of the person and at any moment allows verification that they are complying with the obligations and prohibitions set by the authorities. It enables monitoring of compliance with the obligations set by the judge responsible for the execution of sentences.
Source : ministère de la Justice (site : http://justice.gouv.fr)