  We show the weak convergence, up to extraction of a subsequence, of the
empirical measure for the Keller-Segel system of particles in both subcritical
and critical cases, for general initial conditions. This particle system
consists of $N$ planar Brownian motions interacting through a Coulombian
attractive force, which is quite singular. In the subcritical case, a stronger
result has been established by Bresch-Jabin-Wang \cite{bjw} at the price of two
simplifications: the whole space $\rr^2$ is replaced by a torus and the initial
condition is assumed to be regular. In the subcritical case, our proof is
fairly straightforward: we use a {\it two particles} moment argument, which
shows that particles do not aggregate in finite time, uniformly in the number
of particles. The critical case requires more work.
