Can the Chameleon mechanism explain cosmic acceleration while satisfying
  Solar System constraints ?
  The chameleon mechanism appearing in massive tensor-scalar theory of gravity
can effectively reduce the nonminimal coupling between the scalar field and
matter. This mechanism is invoked to reconcile cosmological data requiring
introduction of Dark Energy with small-scale stringent constraints on General
Relativity. In this communication, we present constraints on this mechanism
obtained by a cosmological analysis (based on Supernovae Ia data) and by a
Solar System analysis (based on PPN formalism).
