This is an announcement for the paper "Free spaces over ultrametric spaces are never isometric to $\ell_1$" by Aude Dalet, Pedro L. Kaufmann, and Antonin Prochazka. Abstract: We show that the Lipschitz free space over an ultrametric space is not isometric to $\ell_1(\Gamma)$ for any set $\Gamma$. Archive classification: math.FA Mathematics Subject Classification: 46B04, 46B20 Submitted from: antonin.prochazka@univ-fcomte.fr The paper may be downloaded from the archive by web browser from URL http://front.math.ucdavis.edu/1502.02719 or http://arXiv.org/abs/1502.02719