  We present experiments to study the relaxation of a nano-scale cylindrical
perturbation at one of the two interfaces of a thin viscous free-standing
polymeric film. Driven by capillarity, the film flows and evolves towards
equilibrium by first symmetrizing the perturbation between the two interfaces,
and eventually broadening the perturbation. A full-Stokes hydrodynamic model is
presented which accounts for both the vertical and lateral flows, and which
highlights the symmetry in the system. The symmetrization time is found to
depend on the membrane thickness, surface tension, and viscosity.
