Fuente: WIPO "circular economy" Described is a tracking system for certifying the origin of a new and/or used article or series of articles (A1, A2), from a predetermined production source (6) wherein an NFC tag device (10) is uniquely associated with the article (A1, A2) or each article (A1, A2) of the series of articles which bear unique reference codes; a smartphone or a tablet (C1, C2, C3, T) detects the unique codes contained in the NFC tag device (10) and transmits them to a remote processing unit (1) designed to prepare on a database (5) a blockchain (B) comprising a series of blocks (B1, B2,... BN) with information and/or transactions designed to certify the origin of the new and/or used article or series of articles (A1, A2) which are subsequently recovered and distributed. A succession of operating instructions installed in the smartphones or in the tablet (C1, C2, C3, T) possessed by the users (U1, U2, U3,... UN) acquires the unique codes of the NFC tag device (10) and the information and/or transactions contained in a ledger (L) are consulted using the remote processing unit (1).