The Cahiers topos is the sheaf topos on the site ThCartSp of infinitessimally thickened cartesian spaces. More generally the higher cahiers topos is the -sheaf -topos on the -site ThCartSp.
However the -topos arising in this way is (still) a 1-localic (i.e. localic) -topos; in other words this notion of higher cahiers topos is no more intelligible than just the classical cahiers topos.
Jacob Lurie, Formal moduli problems
Vladimir Hinich, DG coalgebras as formal stacks, (arXiv:math/9812034