  We construct a moduli scheme for semistable pre-$\D$-modules with prescribed
singularities and numerical data on a smooth projective variety. These
pre-$\D$-modules are to be viewed as regular holonomic $\D$-modules with `level
structure'. We also construct a moduli scheme for perverse sheaves on the
variety with prescribed singularities and other numerical data, and represent
the de Rham functor (which gives the Riemann-Hilbert correspondence) by an
analytic morphism between the two moduli schemes.
