  Context. Hot subdwarfs, which are hot and small He-burning objects, are ideal
targets for exploring the evolution of planetary systems after the red giant
branch (RGB). Thus far, no planets have been confirmed around them, and no
systematic survey to find planets has been carried out. Aims. In this project,
we aim to perform a systematic transit survey in all light curves of hot
subdwarfs from space-based telescopes (Kepler, K2, TESS, and CHEOPS). The goal
is to compute meaningful statistics on two points: firstly, the occurrence
rates of planets around hot subdwarfs, and secondly, the probability of
survival for close-in planets engulfed during the RGB phase of their host. This
paper focuses on the analysis of the observations carried out during cycle 1 of
the TESS mission. Methods. We used our specifically designed pipeline SHERLOCK
to search for transits in the available light curves. When a signal is
detected, it is processed in the next evaluating stages before an object is
qualified for follow-up observations and in-depth analysis to determine the
nature of the transiting body. Results. We applied our method to the 792 hot
subdwarfs observed during cycle 1 of TESS. While 378 interesting signals were
detected in the light curves, only 26 stars were assigned for follow-up
observations. We have identified a series of eclipsing binaries, transiting
white dwarfs, and other types of false positives, but no planet has been
confirmed thus far. A first computation of the upper limit for occurrence rates
was made with the 549 targets displaying no signal. Conclusions. The tools and
method we developed proved their efficiency in analysing the available light
curves from space missions, from detecting an interesting signal to identifying
a transiting planet. This will allow us to fulfil the two main goals of this
project.
