Pancatalogue is the French universities union catalogue of books. In fall 1993, it holds 1,6 million books located in 72 universities. The project has been initiated in 1987 and the catalogue actually started in 1991 by loading 12 universities OCLC data. Two extra types of data from Sibil-France (Montpellier, France) and French Bibliothèque nationale BN-OPALE have since been also integrated. Incoming data are automatically processed through specially designed programs according to the cataloguing rules and format specifications of the three bibliographic record providers, in the aim to automatically achieve a new coherent union catalogue. The paper presents the principles set up for the new database and the input treatements of the data.