Contacts between Piazzi and parisian astronomers are recalled from the time he arrived in Paris in January 1787. There he was mostly with Lalande at the Observatoire de l'Ecole Militaire. In autumn 1787, Piazzi is, with Cassini IV, Legendre and Mechain, participating to the astrogeodetic linkage between the Paris and Greenwich meridian lines. ïazzi was very much appreciated by his French colleagues receiving two time a price from the Academie des sciences.