  Recent observations of binary systems obtained with the H.E.S.S. telescopes
are providing crucial information on the physics of relativistic outflows and
the engines powering them. We report here on new H.E.S.S. results on HESS
J0632+057, PSR B1259-63/LS 2883, Eta Carinae and the recently discovered source
HESS J1018-589. Despite the high-quality data obtained in the last years
through both ground and space-based gamma-ray detectors, many questions on the
mechanisms that permit binary systems to emit at gamma-rays remain open. In
particular, it is becoming apparent that emission at high and very-high
energies is uncorrelated in some gamma-ray binary systems, with bright GeV
flares not observed at TeV energies (e.g. PSR B1259-63), and sources
periodically detected at VHEs which are lacking its HE counterpart (e.g. HESS
J0632+057). Our results mainly confirm the predictions derived previously for
the studied sources, but unexpected results are also found in a few cases,
which are discussed in the context of contemporaneous observations at lower
energies.
