  In a previous paper, an implementable algorithm was introduced to compute
discrete solutions of sweeping processes (i.e. specific first order
differential inclusions). The convergence of this numerical scheme was proved
thanks to compactness arguments. Here we establish that this algorithm is of
order 1/2 . The considered sweeping process involves a set-valued map given by
a finite number of inequality constraints. The proof rests on a metric
qualification condition between the sets associated to each constraint.
