[en] Full text. In order to perform half-life measurements at ALTO, by direct time measurement, we developed a fast-timing set-up using recent LaBr₃ scintillators. We demonstrated first by off-line test with radioactive sources, its efficiency for measuring, by the slope method, half-lives in the [100 ps - some ns] range. Our fast-timing set-up has then been used for measuring half-live of excited states in ¹³⁷;¹³⁹Cs odd-Z nuclei located at, and near, the neutron closed shell N = 82. These neutron-rich Cs isotopes have been obtained at ALTO, from the beta-decay of Xe isotopes produced by the ²³⁸U photo-induced fission. The photons are provided by the slowing down of the electron beam inside the UCX target. The well produced Xe isotopes needed only a low intensity as compared to what ALTO will soon deliver. The ALTO facility at the Orsay Tandem will be briefly described. The main components (photomultiplier, electronic modules) constituting a fast-timing set-up will be presented, their performances in terms of time resolution will be detailed. The different results that we have obtained off-line and online will be discussed. Finally will be presented a recent experiment we performed at the Orsay Tandem, using the Ge detectors of ORGAM in association with our fast-timing set-up in order to realize in a same beam time, indirect and direct time measurements and enlarging the range of reachable half-lives in one experiment. (author)