Eros variable stars: A catalog of Cepheids in the Magellanic Clouds

17 pages, 4 Eps figures, 17 Gif figures Submitted to A&A Suppl., Report with figures of higher quality (99 Eps figures) + catalog are available at http://www-dapnia.cea.fr/Phys/Spp/Experiences/EROS/Cepheides/catalog_cep.htmlWe present a catalog containing 290 LMC and 590 SMC Cepheids which have been obtained using the two 4k $\times$ 8k CCD cameras of the EROS~2 microlensing survey. The Cepheids were selected from 1,134,000 and 504,000 stars in the central regions of the LMC and SMC respectively, that were monitored over 150 nights between October 1996 and February 1997, at a rate of one measurement every night. For each Cepheid the light curves, period, magnitudes in the EROS~2 filter system, Fourier coefficients, J2000 coordinates and cross-identifications with objects referenced in the CDS Simbad database are presented. Finding charts of identified Cepheids in clusters NGC 1943, NGC 1958 and Bruck 56 are presented. The catalogue and the individual light--curves will be electronically available through the CDS (Strasbourg)