  If the spatial sections of the Universe are positively curved, extrapolating
the inflationary stage backward in time inevitably leads to a classical bounce.
This simple scenario, non-singular and free of exotic physics, deserves to be
investigated in details. The background dynamics exhibits interesting features
and is shown to be mostly insensitive to initial conditions as long as
observational consequences are considered. The primordial scalar power spectrum
is explicitly computed, for different inflaton potentials, and the subsequent
CMB temperature anisotropies are calculated. The results are compatible with
current measurements. Some deviations with respect to the standard paradigm can
however appear at large scales and we carefully disentangle what is associated
with the vacuum choice with what is more fundamentally due to the bounce
itself.
