Abstract CUORE (Cryogenic Underground Observatory for Rare Events) is a ton-scale experiment aiming to the search of neutrino-less double beta decay in ¹³⁰Te with a projected sensitivity on the Majorana effective mass close to the inverted hierarchy region. The CUORE detector consists of a segmented array of 988 TeO₂ bolometers, organized in 19 towers and operated at a temperature of about 10 mK thanks to a custom cryogenic system which, besides the uncommon scale, observes several constraints from the radio-purity of the materials to the mechanical decoupling of the cooling systems. The successful commissioning of the CUORE cryogenic system has been completed early in 2016 and represents an outstanding achievement by itself. The installation of the detector proceeded along 2016 followed by the cooldown to base temperature at the beginning of 2017. The CUORE detector is now operational and has been taking science data since Spring 2017. With the first ~3 weeks of collected data, we present here the most stringent constraint on the ¹³⁰Te half-live for the neutrino-less double beta decay.